Encoder, A Decoder And Corresponding Methods For Tile Configuration Signaling

ABSTRACT

The present disclosure provides an encoding and decoding device, as well as an encoding and decoding method. In particular, the present disclosure relates to method for decoding of a video bitstream implemented by a decoding device, wherein the video bitstream includes data representing a coded picture comprising tile columns, the decoding method comprising: obtaining a syntax element by parsing the video bitstream, wherein the syntax element is used to derive the width of the tile columns, wherein the width of the tile columns is uniform; predicting the picture according the width of the tile columns.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/US2019/069137 filed on Dec. 31, 2019, by Futurewei Technologies,Inc., and titled “An Encoder, A Decoder And Corresponding Methods ForTile Configuration Signaling,” which claims the benefit of U.S.Provisional Patent Application No. 62/787,067, filed Dec. 31, 2018, byMaxim Sychev, et al., and titled “Tile Configuration Signaling in VideoCoding,” which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure is generally related to the field of pictureprocessing and more particularly to tile configuration signaling.

BACKGROUND

Video coding (video encoding and decoding) is used in a wide range ofdigital video applications, for example broadcast digital TV, videotransmission over internet and mobile networks, real-time conversationalapplications such as video chat, video conferencing, DVD and Blu-raydiscs, video content acquisition and editing systems, and camcorders ofsecurity applications.

The amount of video data needed to depict even a relatively short videocan be substantial, which may result in difficulties when the data is tobe streamed or otherwise communicated across a communications networkwith limited bandwidth capacity. Thus, video data is generallycompressed before being communicated across modern daytelecommunications networks. The size of a video could also be an issuewhen the video is stored on a storage device because memory resourcesmay be limited. Video compression devices often use software and/orhardware at the source to code the video data prior to transmission orstorage, thereby decreasing the quantity of data needed to representdigital video images. The compressed data is then received at thedestination by a video decompression device that decodes the video data.With limited network resources and ever increasing demands of highervideo quality, improved compression and decompression techniques thatimprove compression ratio with little to no sacrifice in picture qualityare desirable.

SUMMARY

Embodiments of the present application provide apparatuses and methodsfor encoding and decoding according to the independent claims.

The foregoing and other objects are achieved by the subject matter ofthe independent claims. Further implementation forms are apparent fromthe dependent claims, the description and the figures.

Particular embodiments are outlined in the attached independent claims,with other embodiments in the dependent claims.

According to a first aspect the disclosure relates to a method fordecoding of a video bitstream implemented by a decoding device, whereinthe video bitstream includes data representing a coded picturecomprising tile columns, the decoding method comprising: obtaining asyntax element by parsing the video bitstream, wherein the syntaxelement is used to derive a width of the tile columns, wherein the widthof the tile columns are uniform; and predicting the coded pictureaccording the width of the tile columns.

Wherein the syntax element is included in a picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

Wherein the width of the tile columns may be used to locate the CTU in atile of the tile columns in the process of the predicting the codedpicture. For example, determine whether a CTU is the first CTU of thetile, or first CTU of a CTU row of the tile.

In a possible implementation form of the method according to the firstaspect as such, wherein the width of the tile columns are the same.

In a possible implementation form of the method according to anypreceding implementation of the first aspect or the first aspect assuch, wherein the tile columns comprise at least two columns.

According to a second aspect the disclosure relates to a method fordecoding of a video bitstream implemented by a decoding device, whereinthe video bitstream includes data representing a coded picturecomprising a plurality of tile columns, the decoding method comprising:obtaining a syntax element by parsing the video bitstream, wherein thesyntax element is used to derive a width of a tile column of theplurality of tile columns; determining a number of the plurality of tilecolumns based on the width of the tile column; predicting the pictureaccording a width of the tile column and/or the number of the pluralityof tile columns.

Wherein the syntax element is included in the picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

Wherein the width of the tile columns may be used to locate the CTU in atile of the tile columns in the process of the predicting the codedpicture. For example, determine whether a CTU is the first CTU of thetile, or first CTU of a CTU row of the tile.

Wherein the number of the plurality of tile columns may be used tolocate a tile of the tile columns in the process of the predicting thecoded picture.

In a possible implementation form of the method according to the secondaspect as such, wherein the plurality of tile columns comprise one ormore tile columns of which the width are uniform and the one or moretile columns comprise the tile column, the obtaining a syntax element byparsing the video bitstream comprises: obtaining the syntax element byparsing the video bitstream, wherein the syntax element is used toderive the width of the one or more tile columns, wherein the width ofthe tile column comprises the width of the one or more tile columns.

Wherein the one or more tile columns may comprise two or more tilecolumns.

Wherein the syntax element is included in the picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

In a possible implementation form of the method according to anypreceding implementation of the second aspect or the second aspect assuch, wherein the width of the one or more tile columns are the same.

In a possible implementation form of the method according to anypreceding implementation of the second aspect or the second aspect assuch, wherein the one or more tile columns comprise at least twocolumns.

According to a third aspect the disclosure relates to a method of codingimplemented by an encoding device, the coding method comprising:obtaining a width of tile columns in a picture in the process ofencoding the picture, wherein the width of the tile columns are uniform;obtaining a syntax element used to derive the width of the tile columnsaccording to the width of tile columns; encoding the syntax element intoa bitstream of the picture.

Wherein the syntax element is included in the picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

In a possible implementation form of the method according to the thirdaspect as such, wherein the width of the tile columns are the same.

In a possible implementation form of the method according to anypreceding implementation of the third aspect or the third aspect assuch, wherein the tile columns comprise at least two columns.

The method according to the third aspect can be extended intoimplementation forms corresponding to the implementation forms of themethod according to any preceding implementation of the first aspect orthe first aspect. Hence, an implementation form of the method accordingto the third aspect comprises the feature(s) of the correspondingimplementation form of the first aspect.

The advantages of the methods according to the third aspect are the sameas those for the corresponding implementation forms of the methodsaccording to the first aspect.

According to a fourth aspect the disclosure relates to a method ofcoding implemented by an encoding device, the coding method comprising:obtaining a width of a tile column of a plurality of tile columns in apicture; determining a number of the plurality of tile columns based onthe width of the tile column; predicting the picture according to thewidth of the tile column and/or the number of the plurality of tilecolumns.

In a possible implementation form of the method according to the fourthaspect as such, wherein the plurality of tile columns comprise one ormore tile columns of which the width are uniform, the one or more tilecolumns comprise the tile column, and the width of the tile columncomprises the width of the one or more tile columns.

In a possible implementation form of the method according to anypreceding implementation of the fourth aspect or the fourth aspect assuch, wherein the width of the one or more tile columns are the same.

In a possible implementation form of the method according to anypreceding implementation of the fourth aspect or the fourth aspect assuch, wherein the one or more tile columns comprise at least twocolumns.

The method according to the fourth aspect can be extended intoimplementation forms corresponding to the implementation forms of themethod according to any preceding implementation of the second aspect orthe second aspect. Hence, an implementation form of the method accordingto the fourth aspect comprises the feature(s) of the correspondingimplementation form of the second aspect.

The advantages of the methods according to the fourth aspect are thesame as those for the corresponding implementation forms of the methodaccording to the second aspect.

According to a fifth aspect the disclosure relates to a decoding devicefor decoding of a video bitstream, wherein the video bitstream includesdata representing a coded picture comprising tile columns, the decodingdevice comprising: a parsing unit, configured to obtain a syntax elementby parsing the video bitstream, wherein the syntax element is used toderive a width of the tile columns, wherein the width of the tilecolumns are uniform; a predicting unit, configured to predict thepicture according the width of the tile columns.

Wherein the syntax element is included in the picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

In a possible implementation form of the method according to the fifthaspect as such, wherein the width of the tile columns are the same.

In a possible implementation form of the method according to anypreceding implementation of the fifth aspect or the fifth aspect assuch, wherein the tile columns comprise at least two columns.

According to a sixth aspect the disclosure relates to a decoding devicefor decoding of a video bitstream, wherein the video bitstream includesdata representing a coded picture comprising a plurality of tilecolumns, the decoding device comprising: a parsing unit, configured toobtain a syntax element by parsing the video bitstream, wherein thesyntax element is used to derive a width of a tile column of theplurality of tile columns; a determining unit, configured to determine anumber of the plurality of tile columns based on the width of the tilecolumn; a predicting unit, configured to predict the picture accordingto the width of the tile column and/or a number of the plurality of tilecolumns.

In a possible implementation form of the method according to the sixthaspect as such, wherein the plurality of tile columns comprise one ormore tile columns of which the width are uniform and the one or moretile columns comprise the tile column, the parsing unit, configured to:obtain the syntax element by parsing the video bitstream, wherein thesyntax element is used to derive the width of the one or more tilecolumns, wherein the width of the tile column comprises the width of theone or more tile columns.

In a possible implementation form of the method according to anypreceding implementation of the sixth aspect or the sixth aspect assuch, wherein the width of the one or more tile columns are the same.

In a possible implementation form of the method according to anypreceding implementation of the sixth aspect or the sixth aspect assuch, wherein the one or more tile columns comprise at least twocolumns.

According to a seventh aspect the disclosure relates to an encodingdevice, the encoding device comprising: an obtaining unit, configured toobtain a width of tile columns in a picture in the process of encodingthe picture, wherein the width of the tile columns are uniform; andobtain a syntax element used to derive the width of the tile columnsaccording to the width of tile columns; an encoding unit, configured toencode the syntax element into a bitstream of the picture.

In a possible implementation form of the method according to the seventhaspect as such, wherein the width of the tile columns are the same.

In a possible implementation form of the method according to anypreceding implementation of the seventh aspect or the seventh aspect assuch, wherein the tile columns comprise at least two columns.

According to an eighth aspect the disclosure relates to an encodingdevice, the encoding device comprising: an obtaining unit, configured toobtain a width of a tile column of a plurality of tile columns in apicture; a determining unit, configured to determine the number of theplurality of tile columns based on the width of the tile column; apredicting unit, configured to predict the picture according to thewidth of the tile column and/or a number of the plurality of tilecolumns.

In a possible implementation form of the method according to the eighthaspect as such, wherein the plurality of tile columns comprise one ormore tile columns of which the width are uniform, the one or more tilecolumns comprise the tile column, and the width of the tile columncomprises the width of the one or more tile columns.

In a possible implementation form of the method according to anypreceding implementation of the eighth aspect or the eighth aspect assuch, wherein the width of the one or more tile columns are the same.

In a possible implementation form of the method according to anypreceding implementation of the eighth aspect or the eighth aspect assuch, wherein the one or more tile columns comprise at least twocolumns.

According to a ninth aspect the disclosure relates to a decodercomprising processing circuitry for carrying out the method according tothe first aspect, any possible implementation of the first aspect, thesecond aspect or any possible implementation of the second aspect.

According to a tenth aspect the disclosure relates to an encodercomprising processing circuitry for carrying out the method according tothe third aspect, any possible implementation of the third aspect, thefourth aspect or any possible implementation of the fourth aspect.

According to an eleventh aspect the disclosure relates to a computerprogram product comprising program code for performing the methodaccording to any one of the preceding methods when executed on acomputer or a processor.

According to a twelfth aspect the disclosure relates to a decoder,comprising: one or more processors; and a non-transitorycomputer-readable storage medium coupled to the processors and storingprogramming for execution by the processors, wherein the programming,when executed by the processors, configures the decoder to carry out themethod according to any one of the preceding method aspects or anypossible embodiment of the preceding method aspects.

According to a thirteenth aspect the disclosure relates to an encoder,comprising: one or more processors; and a non-transitorycomputer-readable storage medium coupled to the processors and storingprogramming for execution by the processors, wherein the programming,when executed by the processors, configures the encoder to carry out themethod according to any one of the preceding method aspects or anypossible embodiment of the preceding method aspects.

According to a fourteenth aspect the disclosure relates to acomputer-readable medium carrying a program code which, when executed bya computer device, causes the computer device to perform the methodaccording to any one of the preceding method aspects or any possibleembodiment of the preceding method aspects.

According to a fifteenth aspect the disclosure relates to anon-transitory computer-readable medium storing encoded image data, theencoded image data comprising: data of a syntax element used to derive awidth of tile columns according to the width of tile columns in apicture, wherein the width of the tile columns are uniform.

In a possible implementation form of the method according to thefifteenth aspect as such, wherein the width of the tile columns are thesame.

In a possible implementation form of the method according to anypreceding implementation of the fifteenth aspect or the fifteenth aspectas such, wherein the tile columns comprise at least two columns.

According to a sixteenth aspect, the disclosure relates to a computerprogram comprising program code for performing the method according toany one of the preceding method aspects or any possible embodiment ofthe preceding method aspects.

The method according to the first aspect of the disclosure can beperformed by the device according to the fifth aspect of the disclosure.Further features and implementation forms of the device according to thefifth aspect of the disclosure correspond to the features andimplementation forms of the method according to the first aspect of thedisclosure.

The advantages of the devices according to the fifth aspect are the sameas those for the corresponding implementation forms of the methodsaccording to the first aspect.

The method according to the second aspect of the disclosure can beperformed by the apparatus according to the sixth aspect of thedisclosure. Further features and implementation forms of the deviceaccording to the sixth aspect of the disclosure correspond to thefeatures and implementation forms of the method according to the secondaspect of the disclosure.

The advantages of the devices according to the sixth aspect are the sameas those for the corresponding implementation forms of the methodsaccording to the second aspect.

The method according to the third aspect of the disclosure can beperformed by the device according to the seventh aspect of thedisclosure. Further features and implementation forms of the deviceaccording to the seventh aspect of the disclosure correspond to thefeatures and implementation forms of the method according to the thirdaspect of the disclosure.

The advantages of the devices according to the seventh aspect are thesame as those for the corresponding implementation forms of the methodsaccording to the third aspect.

The method according to the fourth aspect of the disclosure can beperformed by the apparatus according to the eighth aspect of thedisclosure. Further features and implementation forms of the deviceaccording to the eighth aspect of the disclosure correspond to thefeatures and implementation forms of the method according to the fourthaspect of the disclosure.

The advantages of the devices according to the eighth aspect are thesame as those for the corresponding implementation forms of the methodsaccording to the fourth aspect.

According to a seventeenth aspect the disclosure relates to a method fordecoding of a video bitstream implemented by a decoding device, whereinthe video bitstream includes data representing a coded picturecomprising tile rows, the decoding method comprising: obtaining a syntaxelement by parsing the video bitstream, wherein the syntax element isused to derive a height of tile rows, wherein the height of the tilerows are uniform; and predicting the coded picture according to theheight of the tile rows.

Wherein the syntax element is included in the picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

Wherein the width of the tile columns may be used to locate the CTU in atile of the tile columns in the process of the predicting the codedpicture.

Wherein the number of the plurality of tile columns may be used tolocate a tile of the tile columns in the process of the predicting thecoded picture or to determine the number of tiles in the coded picture.

In a possible implementation form of the method according to theseventeenth aspect as such, wherein the height of the tile rows are thesame.

In a possible implementation form of the method according to anypreceding implementation of the seventeenth aspect or the seventeenthaspect as such, wherein the tile rows comprise at least two columns.

According to a eighteenth aspect the disclosure relates to a method fordecoding of a video bitstream implemented by a decoding device, whereinthe video bitstream includes data representing a coded picturecomprising a plurality of tile rows, the decoding method comprising:obtaining a syntax element by parsing the video bitstream, wherein thesyntax element is used to derive a height of a tile row of the pluralityof tile rows; determining the number of the plurality of tile rows basedon the height of the tile row; predicting the picture according to theheight of the tile row and/or a number of the plurality of tile rows.

Wherein the syntax element is included in the picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

In a possible implementation form of the method according to theeighteenth aspect as such, wherein the plurality of tile rows compriseone or more tile rows of which the height are uniform and the one ormore tile rows comprise the tile row, the obtaining a syntax element byparsing the video bitstream comprises: obtaining the syntax element byparsing the video bitstream, wherein the syntax element is used toderive the height of the one or more tile rows, wherein the height ofthe tile row comprises the height of the one or more tile rows.

Wherein the one or more tile rows may comprises two or more tile rows.

Wherein the syntax element is included in the picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

In a possible implementation form of the method according to anypreceding implementation of the eighteenth aspect or the eighteenthaspect as such, wherein the height of the one or more tile rows are thesame.

In a possible implementation form of the method according to anypreceding implementation of the eighteenth aspect or the eighteenthaspect as such, wherein the one or more tile rows comprise at least twocolumns.

According to a nineteenth aspect the disclosure relates to a method ofcoding implemented by an encoding device, the coding method comprising:obtaining a height of tile rows in a picture in the process of encodingthe picture, wherein the height of the tile rows are uniform; obtaininga syntax element used to derive the height of the tile rows according tothe height of tile rows; encoding the syntax element into the bitstreamof the picture.

Wherein the syntax element is included in the picture parameter set orpicture header of the video bitstream.

Wherein the picture parameter set or the picture header is related tothe coded picture.

In a possible implementation form of the method according to thenineteenth aspect as such, wherein the height of the tile rows are thesame.

In a possible implementation form of the method according to anypreceding implementation of the nineteenth aspect or the nineteenthaspect as such, wherein the tile rows comprise at least two columns.

The method according to the nineteenth aspect can be extended intoimplementation forms corresponding to the implementation forms of themethod according to any preceding implementation of the seventeenthaspect or the seventeenth aspect. Hence, an implementation form of themethod according to the nineteenth aspect comprises the feature(s) ofthe corresponding implementation form of the seventeenth aspect.

The advantages of the methods according to the nineteenth aspect are thesame as those for the corresponding implementation forms of the methodsaccording to the seventeenth aspect.

According to a twentieth aspect the disclosure relates to a method ofcoding implemented by an encoding device, the coding method comprising:obtaining a height of a tile row of a plurality of tile rows in apicture; determining a number of the plurality of tile rows based on theheight of the tile row; predicting the picture according to the heightof the tile row and/or a number of the plurality of tile rows.

In a possible implementation form of the method according to thetwentieth aspect as such, wherein the plurality of tile rows compriseone or more tile rows of which the height are uniform, the one or moretile rows comprise the tile row, and the height of the tile rowcomprises the height of the one or more tile rows.

In a possible implementation form of the method according to anypreceding implementation of the twentieth aspect or the twentieth aspectas such, wherein the height of the one or more tile rows are the same.

In a possible implementation form of the method according to anypreceding implementation of the twentieth aspect or the twentieth aspectas such, wherein the one or more tile rows comprise at least twocolumns.

The method according to the twentieth aspect can be extended intoimplementation forms corresponding to the implementation forms of themethod according to any preceding implementation of the eighteenthaspect or the eighteenth aspect. Hence, an implementation form of themethod according to the twentieth aspect comprises the feature(s) of thecorresponding implementation form of the eighteenth aspect.

The advantages of the methods according to the twentieth aspect are thesame as those for the corresponding implementation forms of the methodaccording to the eighteenth aspect.

According to a twenty-first aspect the disclosure relates to a decodingdevice for decoding of a video bitstream, wherein the video bitstreamincludes data representing a coded picture comprising tile rows, thedecoding device comprising: a parsing unit, configured to obtain asyntax element by parsing the video bitstream, wherein the syntaxelement is used to derive a height of tile rows, wherein the height ofthe tile rows are uniform; a predicting unit, configured to predict thepicture according to the height of the tile rows.

In a possible implementation form of the method according to thetwenty-first aspect as such, wherein the height of the tile rows are thesame.

In a possible implementation form of the method according to anypreceding implementation of the twenty-first aspect or the twenty-firstaspect as such, wherein the tile rows comprise at least two columns.

According to a twenty-second aspect the disclosure relates to a decodingdevice for decoding of a video bitstream, wherein the video bitstreamincludes data representing a coded picture comprising a plurality oftile rows, the decoding device comprising: a parsing unit, configured toobtain a syntax element by parsing the video bitstream, wherein thesyntax element is used to derive a height of a tile row of the pluralityof tile rows; a determining unit, configured to determine the number ofthe plurality of tile rows based on the height of the tile row; apredicting unit, configured to predict the picture according to theheight of the tile row and/or a number of the plurality of tile rows.

In a possible implementation form of the method according to thetwenty-second aspect as such, wherein the plurality of tile rowscomprise one or more tile rows of which the height are uniform and theone or more tile rows comprise the tile row, the parsing unit,configured to: obtain the syntax element by parsing the video bitstream,wherein the syntax element is used to derive the height of the one ormore tile rows, wherein the height of the tile row comprises the heightof the one or more tile rows.

In a possible implementation form of the method according to anypreceding implementation of the twenty-second aspect or thetwenty-second aspect as such, wherein the height of the one or more tilerows are the same.

In a possible implementation form of the method according to anypreceding implementation of the twenty-second aspect or thetwenty-second aspect as such, wherein the one or more tile rows compriseat least two columns.

According to a twenty-third aspect the disclosure relates to an encodingdevice, the encoding device comprising: an obtaining unit, configured toobtain a height of tile rows in a picture in the process of encoding thepicture, wherein the height of the tile rows are uniform; and obtain asyntax element used to derive the height of the tile rows according tothe height of tile rows; an encoding unit, configured to encode thesyntax element into the bitstream of the picture.

In a possible implementation form of the method according to thetwenty-third aspect as such, wherein the height of the tile rows are thesame.

In a possible implementation form of the method according to anypreceding implementation of the twenty-third aspect or the twenty-thirdaspect as such, wherein the tile rows comprise at least two columns.

According to an twenty-fourth aspect the disclosure relates to anencoding device, the encoding device comprising: an obtaining unit,configured to obtain a height of a tile row of a plurality of tile rowsin a picture; a determining unit, configured to determine a number ofthe plurality of tile rows based on a height of the tile row; apredicting unit, configured to predict the picture according to theheight of the tile row and/or a number of the plurality of tile rows.

In a possible implementation form of the method according to thetwenty-fourth aspect as such, wherein the plurality of tile rowscomprise one or more tile rows of which the height are uniform, the oneor more tile rows comprise the tile row, and the height of the tile rowcomprises the height of the one or more tile rows.

In a possible implementation form of the method according to anypreceding implementation of the twenty-fourth aspect or thetwenty-fourth aspect as such, wherein the height of the one or more tilerows are the same.

In a possible implementation form of the method according to anypreceding implementation of the twenty-fourth aspect or thetwenty-fourth aspect as such, wherein the one or more tile rows compriseat least two columns.

According to a twenty-fifth aspect the disclosure relates to a decodercomprising processing circuitry for carrying out the method according tothe seventeenth aspect, any possible implementation of the seventeenthaspect, the eighteenth aspect or any possible implementation of theeighteenth aspect.

According to a twenty-sixth aspect the disclosure relates to an encodercomprising processing circuitry for carrying out the method according tothe nineteenth aspect, any possible implementation of the nineteenthaspect, the twentieth aspect or any possible implementation of thetwentieth aspect.

According to a twenty-seventh aspect the disclosure relates to acomputer program product comprising program code for performing themethod according to any one of the preceding methods when executed on acomputer or a processor.

According to a twenty-eighth aspect the disclosure relates to decoder,comprising: one or more processors; and a non-transitorycomputer-readable storage medium coupled to the processors and storingprogramming for execution by the processors, wherein the programming,when executed by the processors, configures the decoder to carry out themethod according to any one of the preceding method aspects or anypossible embodiment of the preceding method aspects.

According to a twenty-ninth aspect the disclosure relates to an encoder,comprising: one or more processors; and a non-transitorycomputer-readable storage medium coupled to the processors and storingprogramming for execution by the processors, wherein the programming,when executed by the processors, configures the encoder to carry out themethod according to any one of the preceding method aspects or anypossible embodiment of the preceding method aspects.

According to a thirtieth aspect the disclosure relates to acomputer-readable medium carrying a program code which, when executed bya computer device, causes the computer device to perform the methodaccording to any one of the preceding method aspects or any possibleembodiment of the preceding method aspects.

According to a thirty-first aspect the disclosure relates to anon-transitory computer-readable medium storing encoded image data, theencoded image data comprising: data of a syntax element used to derive aheight of the tile rows according to the height of tile rows in apicture, wherein the height of the tile rows are uniform.

In a possible implementation form of the method according to thethirty-first aspect as such, wherein the height of the tile rows are thesame.

In a possible implementation form of the method according to anypreceding implementation of the thirty-first aspect or the thirty-firstaspect as such, wherein the tile rows comprise at least two columns.

According to a thirty-second aspect, the disclosure relates to acomputer program comprising program code for performing the methodaccording to any one of the preceding method aspects or any possibleembodiment of the preceding method aspects.

The method according to the seventeenth aspect of the disclosure can beperformed by the device according to the twenty-first aspect of thedisclosure. Further features and implementation forms of the deviceaccording to the twenty-first aspect of the disclosure correspond to thefeatures and implementation forms of the method according to theseventeenth aspect of the disclosure.

The advantages of the devices according to the twenty-first aspect arethe same as those for the corresponding implementation forms of themethods according to the seventeenth aspect.

The method according to the eighteenth aspect of the disclosure can beperformed by the apparatus according to the twenty-second aspect of thedisclosure. Further features and implementation forms of the deviceaccording to the twenty-second aspect of the disclosure correspond tothe features and implementation forms of the method according to theeighteenth aspect of the disclosure.

The advantages of the devices according to the twenty-second aspect arethe same as those for the corresponding implementation forms of themethods according to the eighteenth aspect.

The method according to the nineteenth aspect of the disclosure can beperformed by the device according to the twenty-third aspect of thedisclosure. Further features and implementation forms of the deviceaccording to the twenty-third aspect of the disclosure correspond to thefeatures and implementation forms of the method according to thenineteenth aspect of the disclosure.

The advantages of the devices according to the twenty-third aspect arethe same as those for the corresponding implementation forms of themethods according to the nineteenth aspect.

The method according to the twentieth aspect of the disclosure can beperformed by the apparatus according to the twenty-fourth aspect of thedisclosure. Further features and implementation forms of the deviceaccording to the twenty-fourth aspect of the disclosure correspond tothe features and implementation forms of the method according to thetwentieth aspect of the disclosure.

The advantages of the devices according to the twenty-fourth aspect arethe same as those for the corresponding implementation forms of themethods according to the twentieth aspect.

Details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description, drawings, and claims.

For the purpose of clarity, any one of the foregoing embodiments may becombined with any one or more of the other foregoing embodiments tocreate a new embodiment within the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1A is a block diagram showing an example of a video coding systemconfigured to implement embodiments of the disclosure.

FIG. 1B is a block diagram showing another example of a video codingsystem configured to implement embodiments of the disclosure.

FIG. 2 is a block diagram showing an example of a video encoderconfigured to implement embodiments of the disclosure.

FIG. 3 is a block diagram showing an example structure of a videodecoder configured to implement embodiments of the disclosure.

FIG. 4 is a block diagram illustrating an example of an encodingapparatus or a decoding apparatus.

FIG. 5 is a block diagram illustrating another example of an encodingapparatus or a decoding apparatus.

FIG. 6 is an illustrative diagram illustrating an example of extractortrack by using MCTSs of different tile sizes.

FIG. 7 is a flow diagram illustrating a decoding method according to anembodiment.

FIG. 8 is a flow diagram illustrating a decoding method according to anembodiment.

FIG. 9 is a flow diagram illustrating an encoding method according to anembodiment.

FIG. 10 is a flow diagram illustrating an encoding method according toan embodiment.

FIG. 11 is a block diagram illustrating an exemplary decoding device.

FIG. 12 is a block diagram illustrating an exemplary decoding device.

FIG. 13 is a block diagram illustrating an exemplary encoding device.

FIG. 14 is a block diagram illustrating an exemplary encoding device.

FIG. 15 is a block diagram showing an example structure of a contentsupply system which realizes a content delivery service.

FIG. 16 is a block diagram showing a structure of an example of aterminal device.

In the following identical reference signs refer to identical or atleast functionally equivalent features if not explicitly specifiedotherwise.

DETAILED DESCRIPTION

It should be understood at the outset that although an illustrativeimplementation of one or more embodiments are provided below, thedisclosed systems and/or methods may be implemented using any number oftechniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

In the following description, reference is made to the accompanyingfigures, which form part of the disclosure, and which show, by way ofillustration, specific aspects of embodiments of the disclosure orspecific aspects in which embodiments of the present disclosure may beused. It is understood that embodiments of the disclosure may be used inother aspects and comprise structural or logical changes not depicted inthe figures. The following detailed description, therefore, is not to betaken in a limiting sense, and the scope of the present disclosure isdefined by the appended claims.

For instance, it is understood that a disclosure in connection with adescribed method may also hold true for a corresponding device or systemconfigured to perform the method and vice versa. For example, if one ora plurality of specific method steps are described, a correspondingdevice may include one or a plurality of units, e.g. functional units,to perform the described one or plurality of method steps (e.g. one unitperforming the one or plurality of steps, or a plurality of units eachperforming one or more of the plurality of steps), even if such one ormore units are not explicitly described or illustrated in the figures.On the other hand, for example, if a specific apparatus is describedbased on one or a plurality of units, e.g. functional units, acorresponding method may include one step to perform the functionalityof the one or plurality of units (e.g. one step performing thefunctionality of the one or plurality of units, or a plurality of stepseach performing the functionality of one or more of the plurality ofunits), even if such one or plurality of steps are not explicitlydescribed or illustrated in the figures. Further, it is understood thatthe features of the various exemplary embodiments and/or aspectsdescribed herein may be combined with each other, unless specificallynoted otherwise.

Video coding typically refers to the processing of a sequence ofpictures, which form the video or video sequence. Instead of the term“picture” the term “frame” or “image” may be used as synonyms in thefield of video coding. Video coding (or coding in general) comprises twoparts video encoding and video decoding. Video encoding is performed atthe source side, typically comprising processing (e.g. by compression)the original video pictures to reduce the amount of data required forrepresenting the video pictures (for more efficient storage and/ortransmission). Video decoding is performed at the destination side andtypically comprises the inverse processing compared to the encoder toreconstruct the video pictures. Embodiments referring to “coding” ofvideo pictures (or pictures in general) shall be understood to relate to“encoding” or “decoding” of video pictures or respective videosequences. The combination of the encoding part and the decoding part isalso referred to as CODEC (Coding and Decoding).

In case of lossless video coding, the original video pictures can bereconstructed, i.e. the reconstructed video pictures have the samequality as the original video pictures (assuming no transmission loss orother data loss during storage or transmission). In case of lossy videocoding, further compression, e.g. by quantization, is performed, toreduce the amount of data representing the video pictures, which cannotbe completely reconstructed at the decoder, i.e. the quality of thereconstructed video pictures is lower or worse compared to the qualityof the original video pictures.

Several video coding standards belong to the group of “lossy hybridvideo codecs” (i.e. combine spatial and temporal prediction in thesample domain and 2D transform coding for applying quantization in thetransform domain). Each picture of a video sequence is typicallypartitioned into a set of non-overlapping blocks and the coding istypically performed on a block level. In other words, at the encoder thevideo is typically processed, i.e. encoded, on a block (video block)level, e.g. by using spatial (intra picture) prediction and/or temporal(inter picture) prediction to generate a prediction block, subtractingthe prediction block from the current block (block currentlyprocessed/to be processed) to obtain a residual block, transforming theresidual block and quantizing the residual block in the transform domainto reduce the amount of data to be transmitted (compression), whereas atthe decoder the inverse processing compared to the encoder is applied tothe encoded or compressed block to reconstruct the current block forrepresentation. Furthermore, the encoder duplicates the decoderprocessing loop such that both will generate identical predictions (e.g.intra- and inter predictions) and/or re-constructions for processing,i.e. coding, the subsequent blocks.

In the following embodiments of a video coding system 10, a videoencoder 20 and a video decoder 30 are described based on FIGS. 1 to 3.

FIG. 1A is a schematic block diagram illustrating an example codingsystem 10, e.g. a video coding system 10 (or short coding system 10)that may utilize techniques of this present application. Video encoder20 (or short encoder 20) and video decoder 30 (or short decoder 30) ofvideo coding system 10 represent examples of devices that may beconfigured to perform techniques in accordance with various examplesdescribed in the present application.

As shown in FIG. 1A, the coding system 10 comprises a source device 12configured to provide encoded picture data 21 e.g. to a destinationdevice 14 for decoding the encoded picture data 13.

The source device 12 comprises an encoder 20, and may additionally, i.e.optionally, comprise a picture source 16, a pre-processor (orpre-processing unit) 18, e.g. a picture pre-processor 18, and acommunication interface or communication unit 22.

The picture source 16 may comprise or be any kind of picture capturingdevice, for example a camera for capturing a real-world picture, and/orany kind of a picture generating device, for example a computer-graphicsprocessor for generating a computer animated picture, or any kind ofother device for obtaining and/or providing a real-world picture, acomputer generated picture (e.g. a screen content, a virtual reality(VR) picture) and/or any combination thereof (e.g. an augmented reality(AR) picture). The picture source may be any kind of memory or storagestoring any of the aforementioned pictures.

In distinction to the pre-processor 18 and the processing performed bythe pre-processing unit 18, the picture or picture data 17 may also bereferred to as raw picture or raw picture data 17.

Pre-processor 18 is configured to receive the (raw) picture data 17 andto perform pre-processing on the picture data 17 to obtain apre-processed picture 19 or pre-processed picture data 19.Pre-processing performed by the pre-processor 18 may, e.g., comprisetrimming, color format conversion (e.g. from RGB to YCbCr), colorcorrection, or de-noising. It can be understood that the pre-processingunit 18 may be optional component.

The video encoder 20 is configured to receive the pre-processed picturedata 19 and provide encoded picture data 21 (further details will bedescribed below, e.g., based on FIG. 2).

Communication interface 22 of the source device 12 may be configured toreceive the encoded picture data 21 and to transmit the encoded picturedata 21 (or any further processed version thereof) over communicationchannel 13 to another device, e.g. the destination device 14 or anyother device, for storage or direct reconstruction.

The destination device 14 comprises a decoder 30 (e.g. a video decoder30), and may additionally, i.e. optionally, comprise a communicationinterface or communication unit 28, a post-processor 32 (orpost-processing unit 32) and a display device 34.

The communication interface 28 of the destination device 14 isconfigured receive the encoded picture data 21 (or any further processedversion thereof), e.g. directly from the source device 12 or from anyother source, e.g. a storage device, e.g. an encoded picture datastorage device, and provide the encoded picture data 21 to the decoder30.

The communication interface 22 and the communication interface 28 may beconfigured to transmit or receive the encoded picture data 21 or encodeddata 13 via a direct communication link between the source device 12 andthe destination device 14, e.g. a direct wired or wireless connection,or via any kind of network, e.g. a wired or wireless network or anycombination thereof, or any kind of private and public network, or anykind of combination thereof.

The communication interface 22 may be, e.g., configured to package theencoded picture data 21 into an appropriate format, e.g. packets, and/orprocess the encoded picture data using any kind of transmission encodingor processing for transmission over a communication link orcommunication network.

The communication interface 28, forming the counterpart of thecommunication interface 22, may be, e.g., configured to receive thetransmitted data and process the transmission data using any kind ofcorresponding transmission decoding or processing and/or de-packaging toobtain the encoded picture data 21.

Both, communication interface 22 and communication interface 28 may beconfigured as unidirectional communication interfaces as indicated bythe arrow for the communication channel 13 in FIG. 1A pointing from thesource device 12 to the destination device 14, or bi-directionalcommunication interfaces, and may be configured, e.g. to send andreceive messages, e.g. to set up a connection, to acknowledge andexchange any other information related to the communication link and/ordata transmission, e.g. encoded picture data transmission.

The decoder 30 is configured to receive the encoded picture data 21 andprovide decoded picture data 31 or a decoded picture 31 (further detailswill be described below, e.g., based on FIG. 3 or FIG. 5).

The post-processor 32 of destination device 14 is configured topost-process the decoded picture data 31 (also called reconstructedpicture data), e.g. the decoded picture 31, to obtain post-processedpicture data 33, e.g. a post-processed picture 33. The post-processingperformed by the post-processing unit 32 may comprise, e.g. color formatconversion (e.g. from YCbCr to RGB), color correction, trimming, orre-sampling, or any other processing, e.g. for preparing the decodedpicture data 31 for display, e.g. by display device 34.

The display device 34 of the destination device 14 is configured toreceive the post-processed picture data 33 for displaying the picture,e.g. to a user or viewer. The display device 34 may be or comprise anykind of display for representing the reconstructed picture, e.g. anintegrated or external display or monitor. The displays may, e.g.comprise liquid crystal displays (LCD), organic light emitting diodes(OLED) displays, plasma displays, projectors, micro LED displays, liquidcrystal on silicon (LCoS), digital light processor (DLP) or any kind ofother display.

Although FIG. 1A depicts the source device 12 and the destination device14 as separate devices, embodiments of devices may also comprise both orboth functionalities, the source device 12 or correspondingfunctionality and the destination device 14 or correspondingfunctionality. In such embodiments the source device 12 or correspondingfunctionality and the destination device 14 or correspondingfunctionality may be implemented using the same hardware and/or softwareor by separate hardware and/or software or any combination thereof.

As will be apparent for the skilled person based on the description, theexistence and (exact) split of functionalities of the different units orfunctionalities within the source device 12 and/or destination device 14as shown in FIG. 1A may vary depending on the actual device andapplication.

The encoder 20 (e.g. a video encoder 20) or the decoder 30 (e.g. a videodecoder 30) or both encoder 20 and decoder 30 may be implemented viaprocessing circuitry as shown in FIG. 1B, such as one or moremicroprocessors, digital signal processors (DSPs), application-specificintegrated circuits (ASICs), field-programmable gate arrays (FPGAs),discrete logic, hardware, video coding dedicated or any combinationsthereof. The encoder 20 may be implemented via processing circuitry 46to embody the various modules as discussed with respect to encoder 20 ofFIG. 2 and/or any other encoder system or subsystem described herein.The decoder 30 may be implemented via processing circuitry 46 to embodythe various modules as discussed with respect to decoder 30 of FIG. 3and/or any other decoder system or subsystem described herein. Theprocessing circuitry may be configured to perform the various operationsas discussed later. As shown in FIG. 5, if the techniques areimplemented partially in software, a device may store instructions forthe software in a suitable, non-transitory computer-readable storagemedium and may execute the instructions in hardware using one or moreprocessors to perform the techniques of this disclosure. Either of videoencoder 20 and video decoder 30 may be integrated as part of a combinedencoder/decoder (CODEC) in a single device, for example, as shown inFIG. 1B.

Source device 12 and destination device 14 may comprise any of a widerange of devices, including any kind of handheld or stationary devices,e.g. notebook or laptop computers, mobile phones, smart phones, tabletsor tablet computers, cameras, desktop computers, set-top boxes,televisions, display devices, digital media players, video gamingconsoles, video streaming devices (such as content services servers orcontent delivery servers), broadcast receiver device, broadcasttransmitter device, or the like and may use no or any kind of operatingsystem. In some cases, the source device 12 and the destination device14 may be equipped for wireless communication. Thus, the source device12 and the destination device 14 may be wireless communication devices.

In some cases, video coding system 10 illustrated in FIG. 1A is merelyan example and the techniques of the present application may apply tovideo coding settings (e.g., video encoding or video decoding) that donot necessarily include any data communication between the encoding anddecoding devices. In other examples, data is retrieved from a localmemory, streamed over a network, or the like. A video encoding devicemay encode and store data to memory, and/or a video decoding device mayretrieve and decode data from memory. In some examples, the encoding anddecoding is performed by devices that do not communicate with oneanother, but simply encode data to memory and/or retrieve and decodedata from memory.

For convenience of description, embodiments of the disclosure aredescribed herein, for example, by reference to High-Efficiency VideoCoding (HEVC) or to the reference software of Versatile Video coding(VVC), the next generation video coding standard developed by the JointCollaboration Team on Video Coding (JCT-VC) of ITU-T Video CodingExperts Group (VCEG) and ISO/IEC Motion Picture Experts Group (MPEG).One of ordinary skill in the art will understand that embodiments of thedisclosure are not limited to HEVC or VVC.

Encoder and Encoding Method

FIG. 2 shows a schematic block diagram of an example video encoder 20that is configured to implement the techniques of the presentapplication. In the example of FIG. 2, the video encoder 20 comprises aninput 201 (or input interface 201), a residual calculation unit 204, atransform processing unit 206, a quantization unit 208, an inversequantization unit 210, and inverse transform processing unit 212, areconstruction unit 214, a loop filter unit 220, a decoded picturebuffer (DPB) 230, a mode selection unit 260, an entropy encoding unit270 and an output 272 (or output interface 272). The mode selection unit260 may include an inter prediction unit 244, an intra prediction unit254 and a partitioning unit 262. Inter prediction unit 244 may include amotion estimation unit and a motion compensation unit (not shown). Avideo encoder 20 as shown in FIG. 2 may also be referred to as hybridvideo encoder or a video encoder according to a hybrid video codec.

The residual calculation unit 204, the transform processing unit 206,the quantization unit 208, the mode selection unit 260 may be referredto as forming a forward signal path of the encoder 20, whereas theinverse quantization unit 210, the inverse transform processing unit212, the reconstruction unit 214, the buffer 216, the loop filter 220,the decoded picture buffer (DPB) 230, the inter prediction unit 244 andthe intra-prediction unit 254 may be referred to as forming a backwardsignal path of the video encoder 20, wherein the backward signal path ofthe video encoder 20 corresponds to the signal path of the decoder (seevideo decoder 30 in FIG. 3). The inverse quantization unit 210, theinverse transform processing unit 212, the reconstruction unit 214, theloop filter 220, the decoded picture buffer (DPB) 230, the interprediction unit 244 and the intra-prediction unit 254 are also referredto forming the “built-in decoder” of video encoder 20.

Pictures & Picture Partitioning (Pictures & Blocks)

The encoder 20 may be configured to receive, e.g. via input 201, apicture 17 (or picture data 17), e.g. picture of a sequence of picturesforming a video or video sequence. The received picture or picture datamay also be a pre-processed picture 19 (or pre-processed picture data19). For sake of simplicity the following description refers to thepicture 17. The picture 17 may also be referred to as current picture orpicture to be coded (in particular in video coding to distinguish thecurrent picture from other pictures, e.g. previously encoded and/ordecoded pictures of the same video sequence, i.e. the video sequencewhich also comprises the current picture).

A (digital) picture is or can be regarded as a two-dimensional array ormatrix of samples with intensity values. A sample in the array may alsobe referred to as pixel (short form of picture element) or a pel. Thenumber of samples in horizontal and vertical direction (or axis) of thearray or picture define the size and/or resolution of the picture. Forrepresentation of color, typically three color components are employed,i.e. the picture may be represented or include three sample arrays. InRBG format or color space a picture comprises a corresponding red, greenand blue sample array. However, in video coding each pixel is typicallyrepresented in a luminance and chrominance format or color space, e.g.YCbCr, which comprises a luminance component indicated by Y (sometimesalso L is used instead) and two chrominance components indicated by Cband Cr. The luminance (or short luma) component Y represents thebrightness or grey level intensity (e.g. like in a grey-scale picture),while the two chrominance (or short chroma) components Cb and Crrepresent the chromaticity or color information components. Accordingly,a picture in YCbCr format comprises a luminance sample array ofluminance sample values (Y), and two chrominance sample arrays ofchrominance values (Cb and Cr). Pictures in RGB format may be convertedor transformed into YCbCr format and vice versa, the process is alsoknown as color transformation or conversion. If a picture is monochrome,the picture may comprise only a luminance sample array. Accordingly, apicture may be, for example, an array of luma samples in monochromeformat or an array of luma samples and two corresponding arrays ofchroma samples in 4:2:0, 4:2:2, and 4:4:4 color format.

Embodiments of the video encoder 20 may comprise a picture partitioningunit (not depicted in FIG. 2) configured to partition the picture 17into a plurality of (typically non-overlapping) picture blocks 203.These blocks may also be referred to as root blocks, macro blocks(H.264/AVC) or coding tree blocks (CTB) or coding tree units (CTU)(H.265/HEVC and VVC). The picture partitioning unit may be configured touse the same block size for all pictures of a video sequence and thecorresponding grid defining the block size, or to change the block sizebetween pictures or subsets or groups of pictures, and partition eachpicture into the corresponding blocks.

In further embodiments, the video encoder may be configured to receivedirectly a block 203 of the picture 17, e.g. one, several or all blocksforming the picture 17. The picture block 203 may also be referred to ascurrent picture block or picture block to be coded.

Like the picture 17, the picture block 203 again is or can be regardedas a two-dimensional array or matrix of samples with intensity values(sample values), although of smaller dimension than the picture 17. Inother words, the block 203 may comprise, e.g., one sample array (e.g. aluma array in case of a monochrome picture 17, or a luma or chroma arrayin case of a color picture) or three sample arrays (e.g. a luma and twochroma arrays in case of a color picture 17) or any other number and/orkind of arrays depending on the color format applied. The number ofsamples in horizontal and vertical direction (or axis) of the block 203define the size of block 203. Accordingly, a block may, for example, anM×N (M-column by N-row) array of samples, or an M×N array of transformcoefficients.

Embodiments of the video encoder 20 as shown in FIG. 2 may be configuredto encode the picture 17 block by block, e.g. the encoding andprediction is performed per block 203.

Embodiments of the video encoder 20 as shown in FIG. 2 may be furtherconfigured to partition and/or encode the picture by using slices (alsoreferred to as video slices), wherein a picture may be partitioned intoor encoded using one or more slices (typically non-overlapping), andeach slice may comprise one or more blocks (e.g. CTUs) or one or moregroups of blocks (e.g. tiles (H.265/HEVC and VVC) or bricks (VVC)).

Embodiments of the video encoder 20 as shown in FIG. 2 may be furtherconfigured to partition and/or encode the picture by using slices/tilegroups (also referred to as video tile groups) and/or tiles (alsoreferred to as video tiles), wherein a picture may be partitioned intoor encoded using one or more slices/tile groups (typicallynon-overlapping), and each slice/tile group may comprise, e.g. one ormore blocks (e.g. CTUs) or one or more tiles, wherein each tile, e.g.may be of rectangular shape and may comprise one or more blocks (e.g.CTUs), e.g. complete or fractional blocks.

The following specifies how a picture is partitioned into subpictures,slices, and tiles.

A picture is divided into one or more tile rows and one or more tilecolumns. A tile is a sequence of CTUs that covers a rectangular regionof a picture. The CTUs in a tile are scanned in raster scan order withinthat tile.

A slice consists of an integer number of complete tiles or an integernumber of consecutive complete CTU rows within a tile of a picture.

Two modes of slices are supported, namely the raster-scan slice mode andthe rectangular slice mode. In the raster-scan slice mode, a slicecontains a sequence of complete tiles in a tile raster scan of apicture. In the rectangular slice mode, a slice contains either a numberof complete tiles that collectively form a rectangular region of thepicture or a number of consecutive complete CTU rows of one tile thatcollectively form a rectangular region of the picture. Tiles within arectangular slice are scanned in tile raster scan order within therectangular region corresponding to that slice.

A subpicture contains one or more slices that collectively cover arectangular region of a picture.

Pictures are divided into a sequence of coding tree units (CTUs). TheCTU concept is same to that of the HEVC. For a picture that has threesample arrays, a CTU consists of an N×N block of luma samples togetherwith two corresponding blocks of chroma samples.

The maximum allowed size of the luma block in a CTU is specified to be128×128 (although the maximum size of the luma transform blocks is64×64).

Residual Calculation

The residual calculation unit 204 may be configured to calculate aresidual block 205 (also referred to as residual 205) based on thepicture block 203 and a prediction block 265 (further details about theprediction block 265 are provided later), e.g. by subtracting samplevalues of the prediction block 265 from sample values of the pictureblock 203, sample by sample (pixel by pixel) to obtain the residualblock 205 in the sample domain.

Transform

The transform processing unit 206 may be configured to apply atransform, e.g. a discrete cosine transform (DCT) or discrete sinetransform (DST), on the sample values of the residual block 205 toobtain transform coefficients 207 in a transform domain. The transformcoefficients 207 may also be referred to as transform residualcoefficients and represent the residual block 205 in the transformdomain.

The transform processing unit 206 may be configured to apply integerapproximations of DCT/DST, such as the transforms specified forH.265/HEVC. Compared to an orthogonal DCT transform, such integerapproximations are typically scaled by a certain factor. In order topreserve the norm of the residual block which is processed by forwardand inverse transforms, additional scaling factors are applied as partof the transform process. The scaling factors are typically chosen basedon certain constraints like scaling factors being a power of two forshift operations, bit depth of the transform coefficients, tradeoffbetween accuracy and implementation costs, etc. Specific scaling factorsare, for example, specified for the inverse transform, e.g. by inversetransform processing unit 212 (and the corresponding inverse transform,e.g. by inverse transform processing unit 312 at video decoder 30) andcorresponding scaling factors for the forward transform, e.g. bytransform processing unit 206, at an encoder 20 may be specifiedaccordingly.

Embodiments of the video encoder 20 (respectively transform processingunit 206) may be configured to output transform parameters, e.g. a typeof transform or transforms, e.g. directly or encoded or compressed viathe entropy encoding unit 270, so that, e.g., the video decoder 30 mayreceive and use the transform parameters for decoding.

Quantization

The quantization unit 208 may be configured to quantize the transformcoefficients 207 to obtain quantized coefficients 209, e.g. by applyingscalar quantization or vector quantization. The quantized coefficients209 may also be referred to as quantized transform coefficients 209 orquantized residual coefficients 209.

The quantization process may reduce the bit depth associated with someor all of the transform coefficients 207. For example, an n-bittransform coefficient may be rounded down to an m-bit Transformcoefficient during quantization, where n is greater than m. The degreeof quantization may be modified by adjusting a quantization parameter(QP). For example for scalar quantization, different scaling may beapplied to achieve finer or coarser quantization. Smaller quantizationstep sizes correspond to finer quantization, whereas larger quantizationstep sizes correspond to coarser quantization. The applicablequantization step size may be indicated by a quantization parameter(QP). The quantization parameter may for example be an index to apredefined set of applicable quantization step sizes. For example, smallquantization parameters may correspond to fine quantization (smallquantization step sizes) and large quantization parameters maycorrespond to coarse quantization (large quantization step sizes) orvice versa. The quantization may include division by a quantization stepsize and a corresponding and/or the inverse dequantization, e.g. byinverse quantization unit 210, may include multiplication by thequantization step size. Embodiments according to some standards, e.g.HEVC, may be configured to use a quantization parameter to determine thequantization step size. Generally, the quantization step size may becalculated based on a quantization parameter using a fixed pointapproximation of an equation including division. Additional scalingfactors may be introduced for quantization and dequantization to restorethe norm of the residual block, which might get modified because of thescaling used in the fixed point approximation of the equation forquantization step size and quantization parameter. In one exampleimplementation, the scaling of the inverse transform and dequantizationmight be combined. Alternatively, customized quantization tables may beused and signaled from an encoder to a decoder, e.g. in a bitstream. Thequantization is a lossy operation, wherein the loss increases withincreasing quantization step sizes.

Embodiments of the video encoder 20 (respectively quantization unit 208)may be configured to output quantization parameters (QP), e.g. directlyor encoded via the entropy encoding unit 270, so that, e.g., the videodecoder 30 may receive and apply the quantization parameters fordecoding.

Inverse Quantization

The inverse quantization unit 210 is configured to apply the inversequantization of the quantization unit 208 on the quantized coefficientsto obtain dequantized coefficients 211, e.g. by applying the inverse ofthe quantization scheme applied by the quantization unit 208 based on orusing the same quantization step size as the quantization unit 208. Thedequantized coefficients 211 may also be referred to as dequantizedresidual coefficients 211 and correspond—although typically notidentical to the transform coefficients due to the loss byquantization—to the transform coefficients 207.

Inverse Transform

The inverse transform processing unit 212 is configured to apply theinverse transform of the transform applied by the transform processingunit 206, e.g. an inverse discrete cosine transform (DCT) or inversediscrete sine transform (DST) or other inverse transforms, to obtain areconstructed residual block 213 (or corresponding dequantizedcoefficients 213) in the sample domain. The reconstructed residual block213 may also be referred to as transform block 213.

Reconstruction

The reconstruction unit 214 (e.g. adder or summer 214) is configured toadd the transform block 213 (i.e. reconstructed residual block 213) tothe prediction block 265 to obtain a reconstructed block 215 in thesample domain, e.g. by adding—sample by sample—the sample values of thereconstructed residual block 213 and the sample values of the predictionblock 265.

Filtering

The loop filter unit 220 (or short “loop filter” 220), is configured tofilter the reconstructed block 215 to obtain a filtered block 221, or ingeneral, to filter reconstructed samples to obtain filtered samplevalues. The loop filter unit is, e.g., configured to smooth pixeltransitions, or otherwise improve the video quality. The loop filterunit 220 may comprise one or more loop filters such as a de-blockingfilter, a sample-adaptive offset (SAO) filter or one or more otherfilters, e.g. an adaptive loop filter (ALF), a noise suppression filter(NSF), or any combination thereof. In an example, the loop filter unit220 may comprise a de-blocking filter, a SAO filter and an ALF filter.The order of the filtering process may be the deblocking filter, SAO andALF. In another example, a process called the luma mapping with chromascaling (LMCS) (namely, the adaptive in-loop reshaper) is added. Thisprocess is performed before deblocking. In another example, thedeblocking filter process may be also applied to internal sub-blockedges, e.g. affine sub-blocks edges, ATMVP sub-blocks edges, sub-blocktransform (SBT) edges and intra sub-partition (ISP) edges. Although theloop filter unit 220 is shown in FIG. 2 as being an in loop filter, inother configurations, the loop filter unit 220 may be implemented as apost loop filter. The filtered block 221 may also be referred to asfiltered reconstructed block 221.

Embodiments of the video encoder 20 (respectively loop filter unit 220)may be configured to output loop filter parameters (such as SAO filterparameters or ALF filter parameters or LMCS parameters), e.g. directlyor encoded via the entropy encoding unit 270, so that, e.g., a decoder30 may receive and apply the same loop filter parameters or respectiveloop filters for decoding.

Decoded Picture Buffer

The decoded picture buffer (DPB) 230 may be a memory that storesreference pictures, or in general reference picture data, for encodingvideo data by video encoder 20. The DPB 230 may be formed by any of avariety of memory devices, such as dynamic random access memory (DRAM),including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM),resistive RAM (RRAM), or other types of memory devices. The decodedpicture buffer (DPB) 230 may be configured to store one or more filteredblocks 221. The decoded picture buffer 230 may be further configured tostore other previously filtered blocks, e.g. previously reconstructedand filtered blocks 221, of the same current picture or of differentpictures, e.g. previously reconstructed pictures, and may providecomplete previously reconstructed, i.e. decoded, pictures (andcorresponding reference blocks and samples) and/or a partiallyreconstructed current picture (and corresponding reference blocks andsamples), for example for inter prediction. The decoded picture buffer(DPB) 230 may be also configured to store one or more unfilteredreconstructed blocks 215, or in general unfiltered reconstructedsamples, e.g. if the reconstructed block 215 is not filtered by loopfilter unit 220, or any other further processed version of thereconstructed blocks or samples.

Mode Selection (Partitioning & Prediction)

The mode selection unit 260 comprises partitioning unit 262,inter-prediction unit 244 and intra-prediction unit 254, and isconfigured to receive or obtain original picture data, e.g. an originalblock 203 (current block 203 of the current picture 17), andreconstructed picture data, e.g. filtered and/or unfilteredreconstructed samples or blocks of the same (current) picture and/orfrom one or a plurality of previously decoded pictures, e.g. fromdecoded picture buffer 230 or other buffers (e.g. line buffer, notshown). The reconstructed picture data is used as reference picture datafor prediction, e.g. inter-prediction or intra-prediction, to obtain aprediction block 265 or predictor 265.

Mode selection unit 260 may be configured to determine or select apartitioning for a current block prediction mode (including nopartitioning) and a prediction mode (e.g. an intra or inter predictionmode) and generate a corresponding prediction block 265, which is usedfor the calculation of the residual block 205 and for the reconstructionof the reconstructed block 215.

Embodiments of the mode selection unit 260 may be configured to selectthe partitioning and the prediction mode (e.g. from those supported byor available for mode selection unit 260), which provide the best matchor in other words the minimum residual (minimum residual means bettercompression for transmission or storage), or a minimum signalingoverhead (minimum signaling overhead means better compression fortransmission or storage), or which considers or balances both. The modeselection unit 260 may be configured to determine the partitioning andprediction mode based on rate distortion optimization (RDO), i.e. selectthe prediction mode which provides a minimum rate distortion. Terms like“best”, “minimum”, “optimum” etc. in this context do not necessarilyrefer to an overall “best”, “minimum”, “optimum”, etc. but may alsorefer to the fulfillment of a termination or selection criterion like avalue exceeding or falling below a threshold or other constraintsleading potentially to a “sub-optimum selection” but reducing complexityand processing time.

In other words, the partitioning unit 262 may be configured to partitiona picture from a video sequence into a sequence of coding tree units(CTUs), and the CTU 203 may be further partitioned into smaller blockpartitions or sub-blocks (which form again blocks), e.g. iterativelyusing quad-tree-partitioning (QT), binary partitioning (BT) ortriple-tree-partitioning (TT) or any combination thereof, and toperform, e.g., the prediction for each of the block partitions orsub-blocks, wherein the mode selection comprises the selection of thetree-structure of the partitioned block 203 and the prediction modes areapplied to each of the block partitions or sub-blocks.

In the following the partitioning (e.g. by partitioning unit 260) andprediction processing (by inter-prediction unit 244 and intra-predictionunit 254) performed by an example video encoder 20 will be explained inmore detail.

Partitioning

The partitioning unit 262 may be configured to partition a picture froma video sequence into a sequence of coding tree units (CTUs), and thepartitioning unit 262 may partition (or split) a coding tree unit (CTU)203 into smaller partitions, e.g. smaller blocks of square orrectangular size. For a picture that has three sample arrays, a CTUconsists of an N×N block of luma samples together with two correspondingblocks of chroma samples. The maximum allowed size of the luma block ina CTU is specified to be 128×128 in the developing versatile videocoding (VVC), but it can be specified to be value rather than 128×128 inthe future, for example, 256×256. The CTUs of a picture may beclustered/grouped as slices/tile groups, tiles or bricks. A tile coversa rectangular region of a picture, and a tile can be divided into one ormore bricks. A brick consists of a number of CTU rows within a tile. Atile that is not partitioned into multiple bricks can be referred to asa brick. However, a brick is a true subset of a tile and is not referredto as a tile. There are two modes of tile groups are supported in VVC,namely the raster-scan slice/tile group mode and the rectangular slicemode. In the raster-scan tile group mode, a slice/tile group contains asequence of tiles in tile raster scan of a picture. In the rectangularslice mode, a slice contains a number of bricks of a picture thatcollectively form a rectangular region of the picture. The bricks withina rectangular slice are in the order of brick raster scan of the slice.These smaller blocks (which may also be referred to as sub-blocks) maybe further partitioned into even smaller partitions. This is alsoreferred to tree-partitioning or hierarchical tree-partitioning, whereina root block, e.g. at root tree-level 0 (hierarchy-level 0, depth 0),may be recursively partitioned, e.g. partitioned into two or more blocksof a next lower tree-level, e.g. nodes at tree-level 1 (hierarchy-level1, depth 1), wherein these blocks may be again partitioned into two ormore blocks of a next lower level, e.g. tree-level 2 (hierarchy-level 2,depth 2), etc. until the partitioning is terminated, e.g. because atermination criterion is fulfilled, e.g. a maximum tree depth or minimumblock size is reached. Blocks which are not further partitioned are alsoreferred to as leaf-blocks or leaf nodes of the tree. A tree usingpartitioning into two partitions is referred to as binary-tree (BT), atree using partitioning into three partitions is referred to asternary-tree (TT), and a tree using partitioning into four partitions isreferred to as quad-tree (QT).

For example, a coding tree unit (CTU) may be or comprise a CTB of lumasamples, two corresponding CTBs of chroma samples of a picture that hasthree sample arrays, or a CTB of samples of a monochrome picture or apicture that is coded using three separate colour planes and syntaxstructures used to code the samples. Correspondingly, a coding treeblock (CTB) may be an N×N block of samples for some value of N such thatthe division of a component into CTBs is a partitioning. A coding unit(CU) may be or comprise a coding block of luma samples, twocorresponding coding blocks of chroma samples of a picture that hasthree sample arrays, or a coding block of samples of a monochromepicture or a picture that is coded using three separate colour planesand syntax structures used to code the samples. Correspondingly a codingblock (CB) may be an M×N block of samples for some values of M and Nsuch that the division of a CTB into coding blocks is a partitioning.

In embodiments, e.g., according to HEVC, a coding tree unit (CTU) may besplit into CUs by using a quad-tree structure denoted as coding tree.The decision whether to code a picture area using inter-picture(temporal) or intra-picture (spatial) prediction is made at the leaf CUlevel. Each leaf CU can be further split into one, two or four PUsaccording to the PU splitting type. Inside one PU, the same predictionprocess is applied and the relevant information is transmitted to thedecoder on a PU basis. After obtaining the residual block by applyingthe prediction process based on the PU splitting type, a leaf CU can bepartitioned into transform units (TUs) according to another quadtreestructure similar to the coding tree for the CU.

In embodiments, e.g., according to the latest video coding standardcurrently in development, which is referred to as Versatile Video Coding(VVC), a combined Quad-tree nested multi-type tree using binary andternary splits segmentation structure for example used to partition acoding tree unit. In the coding tree structure within a coding treeunit, a CU can have either a square or rectangular shape. For example,the coding tree unit (CTU) is first partitioned by a quaternary tree.Then the quaternary tree leaf nodes can be further partitioned by amulti-type tree structure. There are four splitting types in multi-typetree structure, vertical binary splitting (SPLIT_BT_VER), horizontalbinary splitting (SPLIT_BT_HOR), vertical ternary splitting(SPLIT_TT_VER), and horizontal ternary splitting (SPLIT_TT_HOR). Themulti-type tree leaf nodes are called coding units (CUs), and unless theCU is too large for the maximum transform length, this segmentation isused for prediction and transform processing without any furtherpartitioning. This means that, in most cases, the CU, PU and TU have thesame block size in the quadtree with nested multi-type tree coding blockstructure. The exception occurs when maximum supported transform lengthis smaller than the width or height of the color component of the CU.VVCdevelops a unique signaling mechanism of the partition splittinginformation in quadtree with nested multi-type tree coding treestructure. In the signaling mechanism, a coding tree unit (CTU) istreated as the root of a quaternary tree and is first partitioned by aquaternary tree structure. Each quaternary tree leaf node (whensufficiently large to allow it) is then further partitioned by amulti-type tree structure. In the multi-type tree structure, a firstflag (mtt_split_cu_flag) is signaled to indicate whether the node isfurther partitioned; when a node is further partitioned, a second flag(mtt_split_cu_vertical_flag) is signaled to indicate the splittingdirection, and then a third flag (mtt_split_cu_binary_flag) is signaledto indicate whether the split is a binary split or a ternary split.Based on the values of mtt_split_cu_vertical_flag andmtt_split_cu_binary_flag, the multi-type tree slitting mode(MttSplitMode) of a CU can be derived by a decoder based on a predefinedrule or a table. It should be noted, for a certain design, for example,64×64 Luma block and 32×32 Chroma pipelining design in VVC hardwaredecoders, TT split is forbidden when either width or height of a lumacoding block is larger than 64, as shown in FIG. 6. TT split is alsoforbidden when either width or height of a chroma coding block is largerthan 32. The pipelining design will divide a picture into Virtualpipeline data units s(VPDUs) which are defined as non-overlapping unitsin a picture. In hardware decoders, successive VPDUs are processed bymultiple pipeline stages simultaneously. The VPDU size is roughlyproportional to the buffer size in most pipeline stages, so it isimportant to keep the VPDU size small. In most hardware decoders, theVPDU size can be set to maximum transform block (TB) size. However, inVVC, ternary tree (TT) and binary tree (BT) partition may lead to theincreasing of VPDUs sizes.

In addition, it should be noted that, when a portion of a tree nodeblock exceeds the bottom or right picture boundary, the tree node blockis forced to be split until the all samples of every coded CU arelocated inside the picture boundaries.

As an example, the Intra Sub-Partitions (ISP) tool may divide lumaintra-predicted blocks vertically or horizontally into 2 or 4sub-partitions depending on the block size.

In one example, the mode selection unit 260 of video encoder 20 may beconfigured to perform any combination of the partitioning techniquesdescribed herein.

As described above, the video encoder 20 is configured to determine orselect the best or an optimum prediction mode from a set of (e.g.pre-determined) prediction modes. The set of prediction modes maycomprise, e.g., intra-prediction modes and/or inter-prediction modes.

Intra-Prediction

The set of intra-prediction modes may comprise 35 differentintra-prediction modes, e.g. non-directional modes like DC (or mean)mode and planar mode, or directional modes, e.g. as defined in HEVC, ormay comprise 67 different intra-prediction modes, e.g. non-directionalmodes like DC (or mean) mode and planar mode, or directional modes, e.g.as defined for VVC. As an example, several conventional angular intraprediction modes are adaptively replaced with wide-angle intraprediction modes for the non-square blocks, e.g. as defined in VVC. Asanother example, to avoid division operations for DC prediction, onlythe longer side is used to compute the average for non-square blocks.And, the results of intra prediction of planar mode may be furthermodified by a position dependent intra prediction combination (PDPC)method.

The intra-prediction unit 254 is configured to use reconstructed samplesof neighboring blocks of the same current picture to generate anintra-prediction block 265 according to an intra-prediction mode of theset of intra-prediction modes.

The intra prediction unit 254 (or in general the mode selection unit260) is further configured to output intra-prediction parameters (or ingeneral information indicative of the selected intra prediction mode forthe block) to the entropy encoding unit 270 in form of syntax elements266 for inclusion into the encoded picture data 21, so that, e.g., thevideo decoder 30 may receive and use the prediction parameters fordecoding.

Inter-Prediction

The set of (or possible) inter-prediction modes depends on the availablereference pictures (i.e. previous at least partially decoded pictures,e.g. stored in DBP 230) and other inter-prediction parameters, e.g.whether the whole reference picture or only a part, e.g. a search windowarea around the area of the current block, of the reference picture isused for searching for a best matching reference block, and/or e.g.whether pixel interpolation is applied, e.g. half/semi-pel, quarter-peland/or 1/16 pel interpolation, or not.

Additional to the above prediction modes, skip mode, direct mode and/orother inter prediction mode may be applied.

For example, Extended merge prediction, the merge candidate list of suchmode is constructed by including the following five types of candidatesin order: Spatial MVP from spatial neighbor CUs, Temporal MVP fromcollocated CUs, History-based MVP from an FIFO table, Pairwise averageMVP and Zero MVs. And a bilateral-matching based decoder side motionvector refinement (DMVR) may be applied to increase the accuracy of theMVs of the merge mode. Merge mode with MVD (MMVD), which comes frommerge mode with motion vector differences. A MMVD flag is signaled rightafter sending a skip flag and merge flag to specify whether MMVD mode isused for a CU. And a CU-level adaptive motion vector resolution (AMVR)scheme may be applied. AMVR allows MVD of the CU to be coded indifferent precision. Dependent on the prediction mode for the currentCU, the MVDs of the current CU can be adaptively selected. When a CU iscoded in merge mode, the combined inter/intra prediction (CIIP) mode maybe applied to the current CU. Weighted averaging of the inter and intraprediction signals is performed to obtain the CIIP prediction. Affinemotion compensated prediction, the affine motion field of the block isdescribed by motion information of two control point (4-parameter) orthree control point motion vectors (6-parameter). Subblock-basedtemporal motion vector prediction (SbTMVP), which is similar to thetemporal motion vector prediction (TMVP) in HEVC, but predicts themotion vectors of the sub-CUs within the current CU. Bi-directionaloptical flow (BDOF), previously referred to as BIO, is a simpler versionthat requires much less computation, especially in terms of number ofmultiplications and the size of the multiplier. Triangle partition mode,in such a mode, a CU is split evenly into two triangle-shapedpartitions, using either the diagonal split or the anti-diagonal split.Besides, the bi-prediction mode is extended beyond simple averaging toallow weighted averaging of the two prediction signals.

The inter prediction unit 244 may include a motion estimation (ME) unitand a motion compensation (MC) unit (both not shown in FIG. 2). Themotion estimation unit may be configured to receive or obtain thepicture block 203 (current picture block 203 of the current picture 17)and a decoded picture 231, or at least one or a plurality of previouslyreconstructed blocks, e.g. reconstructed blocks of one or a plurality ofother/different previously decoded pictures 231, for motion estimation.E.g. a video sequence may comprise the current picture and thepreviously decoded pictures 231, or in other words, the current pictureand the previously decoded pictures 231 may be part of or form asequence of pictures forming a video sequence.

The encoder 20 may, e.g., be configured to select a reference block froma plurality of reference blocks of the same or different pictures of theplurality of other pictures and provide a reference picture (orreference picture index) and/or an offset (spatial offset) between theposition (x, y coordinates) of the reference block and the position ofthe current block as inter prediction parameters to the motionestimation unit. This offset is also called motion vector (MV).

The motion compensation unit is configured to obtain, e.g. receive, aninter prediction parameter and to perform inter prediction based on orusing the inter prediction parameter to obtain an inter prediction block265. Motion compensation, performed by the motion compensation unit, mayinvolve fetching or generating the prediction block based on themotion/block vector determined by motion estimation, possibly performinginterpolations to sub-pixel precision. Interpolation filtering maygenerate additional pixel samples from known pixel samples, thuspotentially increasing the number of candidate prediction blocks thatmay be used to code a picture block. Upon receiving the motion vectorfor the PU of the current picture block, the motion compensation unitmay locate the prediction block to which the motion vector points in oneof the reference picture lists.

The motion compensation unit may also generate syntax elementsassociated with the blocks and video slices for use by video decoder 30in decoding the picture blocks of the video slice. In addition or as analternative to slices and respective syntax elements, tile groups and/ortiles and respective syntax elements may be generated or used.

Entropy Coding

The entropy encoding unit 270 is configured to apply, for example, anentropy encoding algorithm or scheme (e.g. a variable length coding(VLC) scheme, an context adaptive VLC scheme (CAVLC), an arithmeticcoding scheme, a binarization, a context adaptive binary arithmeticcoding (CABAC), syntax-based context-adaptive binary arithmetic coding(SBAC), probability interval partitioning entropy (PIPE) coding oranother entropy encoding methodology or technique) or bypass (nocompression) on the quantized coefficients 209, inter predictionparameters, intra prediction parameters, loop filter parameters and/orother syntax elements to obtain encoded picture data 21 which can beoutput via the output 272, e.g. in the form of an encoded bitstream 21,so that, e.g., the video decoder 30 may receive and use the parametersfor decoding. The encoded bitstream 21 may be transmitted to videodecoder 30, or stored in a memory for later transmission or retrieval byvideo decoder 30.

Other structural variations of the video encoder 20 can be used toencode the video stream. For example, a non-transform based encoder 20can quantize the residual signal directly without the transformprocessing unit 206 for certain blocks or frames. In anotherimplementation, an encoder 20 can have the quantization unit 208 and theinverse quantization unit 210 combined into a single unit.

Decoder and Decoding Method

FIG. 3 shows an example of a video decoder 30 that is configured toimplement the techniques of this present application. The video decoder30 is configured to receive encoded picture data 21 (e.g. encodedbitstream 21), e.g. encoded by encoder 20, to obtain a decoded picture331. The encoded picture data or bitstream comprises information fordecoding the encoded picture data, e.g. data that represents pictureblocks of an encoded video slice (and/or tile groups or tiles) andassociated syntax elements.

In the example of FIG. 3, the decoder 30 comprises an entropy decodingunit 304, an inverse quantization unit 310, an inverse transformprocessing unit 312, a reconstruction unit 314 (e.g. a summer 314), aloop filter 320, a decoded picture buffer (DBP) 330, a mode applicationunit 360, an inter prediction unit 344 and an intra prediction unit 354.Inter prediction unit 344 may be or include a motion compensation unit.Video decoder 30 may, in some examples, perform a decoding passgenerally reciprocal to the encoding pass described with respect tovideo encoder 100 from FIG. 2.

As explained with regard to the encoder 20, the inverse quantizationunit 210, the inverse transform processing unit 212, the reconstructionunit 214, the loop filter 220, the decoded picture buffer (DPB) 230, theinter prediction unit 344 and the intra prediction unit 354 are alsoreferred to as forming the “built-in decoder” of video encoder 20.Accordingly, the inverse quantization unit 310 may be identical infunction to the inverse quantization unit 110, the inverse transformprocessing unit 312 may be identical in function to the inversetransform processing unit 212, the reconstruction unit 314 may beidentical in function to reconstruction unit 214, the loop filter 320may be identical in function to the loop filter 220, and the decodedpicture buffer 330 may be identical in function to the decoded picturebuffer 230. Therefore, the explanations provided for the respectiveunits and functions of the video 20 encoder apply correspondingly to therespective units and functions of the video decoder 30.

Entropy Decoding

The entropy decoding unit 304 is configured to parse the bitstream 21(or in general encoded picture data 21) and perform, for example,entropy decoding to the encoded picture data 21 to obtain, e.g.,quantized coefficients 309 and/or decoded coding parameters (not shownin FIG. 3), e.g. any or all of inter prediction parameters (e.g.reference picture index and motion vector), intra prediction parameter(e.g. intra prediction mode or index), transform parameters,quantization parameters, loop filter parameters, and/or other syntaxelements. Entropy decoding unit 304 maybe configured to apply thedecoding algorithms or schemes corresponding to the encoding schemes asdescribed with regard to the entropy encoding unit 270 of the encoder20. Entropy decoding unit 304 may be further configured to provide interprediction parameters, intra prediction parameter and/or other syntaxelements to the mode application unit 360 and other parameters to otherunits of the decoder 30. Video decoder 30 may receive the syntaxelements at the video slice level and/or the video block level. Inaddition or as an alternative to slices and respective syntax elements,tile groups and/or tiles and respective syntax elements may be receivedand/or used.

Inverse Quantization

The inverse quantization unit 310 may be configured to receivequantization parameters (QP) (or in general information related to theinverse quantization) and quantized coefficients from the encodedpicture data 21 (e.g. by parsing and/or decoding, e.g. by entropydecoding unit 304) and to apply based on the quantization parameters aninverse quantization on the decoded quantized coefficients 309 to obtaindequantized coefficients 311, which may also be referred to as transformcoefficients 311. The inverse quantization process may include use of aquantization parameter determined by video encoder 20 for each videoblock in the video slice (or tile or tile group) to determine a degreeof quantization and, likewise, a degree of inverse quantization thatshould be applied.

Inverse Transform

Inverse transform processing unit 312 may be configured to receivedequantized coefficients 311, also referred to as transform coefficients311, and to apply a transform to the dequantized coefficients 311 inorder to obtain reconstructed residual blocks 213 in the sample domain.The reconstructed residual blocks 213 may also be referred to astransform blocks 313. The transform may be an inverse transform, e.g.,an inverse DCT, an inverse DST, an inverse integer transform, or aconceptually similar inverse transform process. The inverse transformprocessing unit 312 may be further configured to receive transformparameters or corresponding information from the encoded picture data 21(e.g. by parsing and/or decoding, e.g. by entropy decoding unit 304) todetermine the transform to be applied to the dequantized coefficients311.

Reconstruction

The reconstruction unit 314 (e.g. adder or summer 314) may be configuredto add the reconstructed residual block 313, to the prediction block 365to obtain a reconstructed block 315 in the sample domain, e.g. by addingthe sample values of the reconstructed residual block 313 and the samplevalues of the prediction block 365.

Filtering

The loop filter unit 320 (either in the coding loop or after the codingloop) is configured to filter the reconstructed block 315 to obtain afiltered block 321, e.g. to smooth pixel transitions, or otherwiseimprove the video quality. The loop filter unit 320 may comprise one ormore loop filters such as a de-blocking filter, a sample-adaptive offset(SAO) filter or one or more other filters, e.g. an adaptive loop filter(ALF), a noise suppression filter (NSF), or any combination thereof. Inan example, the loop filter unit 220 may comprise a de-blocking filter,a SAO filter and an ALF filter. The order of the filtering process maybe the deblocking filter, SAO and ALF. In another example, a processcalled the luma mapping with chroma scaling (LMCS) (namely, the adaptivein-loop reshaper) is added. This process is performed before deblocking.In another example, the deblocking filter process may be also applied tointernal sub-block edges, e.g. affine sub-blocks edges, ATMVP sub-blocksedges, sub-block transform (SBT) edges and intra sub-partition (ISP)edges. Although the loop filter unit 320 is shown in FIG. 3 as being anin loop filter, in other configurations, the loop filter unit 320 may beimplemented as a post loop filter.

Decoded Picture Buffer

The decoded video blocks 321 of a picture are then stored in decodedpicture buffer 330, which stores the decoded pictures 331 as referencepictures for subsequent motion compensation for other pictures and/orfor output respectively display.

The decoder 30 is configured to output the decoded picture 311, e.g. viaoutput 312, for presentation or viewing to a user.

Prediction

The inter prediction unit 344 may be identical to the inter predictionunit 244 (in particular to the motion compensation unit) and the intraprediction unit 354 may be identical to the inter prediction unit 254 infunction, and performs split or partitioning decisions and predictionbased on the partitioning and/or prediction parameters or respectiveinformation received from the encoded picture data 21 (e.g. by parsingand/or decoding, e.g. by entropy decoding unit 304). Mode applicationunit 360 may be configured to perform the prediction (intra or interprediction) per block based on reconstructed pictures, blocks orrespective samples (filtered or unfiltered) to obtain the predictionblock 365.

When the video slice is coded as an intra coded (I) slice, intraprediction unit 354 of mode application unit 360 is configured togenerate prediction block 365 for a picture block of the current videoslice based on a signaled intra prediction mode and data from previouslydecoded blocks of the current picture. When the video picture is codedas an inter coded (i.e., B, or P) slice, inter prediction unit 344 (e.g.motion compensation unit) of mode application unit 360 is configured toproduce prediction blocks 365 for a video block of the current videoslice based on the motion vectors and other syntax elements receivedfrom entropy decoding unit 304. For inter prediction, the predictionblocks may be produced from one of the reference pictures within one ofthe reference picture lists. Video decoder 30 may construct thereference frame lists, List 0 and List 1, using default constructiontechniques based on reference pictures stored in DPB 330. The same orsimilar may be applied for or by embodiments using tile groups (e.g.video tile groups) and/or tiles (e.g. video tiles) in addition oralternatively to slices (e.g. video slices), e.g. a video may be codedusing I, P or B tile groups and/or tiles.

Mode application unit 360 is configured to determine the predictioninformation for a video block of the current video slice by parsing themotion vectors or related information and other syntax elements, anduses the prediction information to produce the prediction blocks for thecurrent video block being decoded. For example, the mode applicationunit 360 uses some of the received syntax elements to determine aprediction mode (e.g., intra or inter prediction) used to code the videoblocks of the video slice, an inter prediction slice type (e.g., Bslice, P slice, or GPB slice), construction information for one or moreof the reference picture lists for the slice, motion vectors for eachinter encoded video block of the slice, inter prediction status for eachinter coded video block of the slice, and other information to decodethe video blocks in the current video slice. The same or similar may beapplied for or by embodiments using tile groups (e.g. video tile groups)and/or tiles (e.g. video tiles) in addition or alternatively to slices(e.g. video slices), e.g. a video may be coded using I, P or B tilegroups and/or tiles.

Embodiments of the video decoder 30 as shown in FIG. 3 may be configuredto partition and/or decode the picture by using slices (also referred toas video slices), wherein a picture may be partitioned into or decodedusing one or more slices (typically non-overlapping), and each slice maycomprise one or more blocks (e.g. CTUs) or one or more groups of blocks(e.g. tiles (H.265/HEVC and VVC) or bricks (VVC)).

Embodiments of the video decoder 30 as shown in FIG. 3 may be configuredto partition and/or decode the picture by using slices/tile groups (alsoreferred to as video tile groups) and/or tiles (also referred to asvideo tiles), wherein a picture may be partitioned into or decoded usingone or more slices/tile groups (typically non-overlapping), and eachslice/tile group may comprise, e.g. one or more blocks (e.g. CTUs) orone or more tiles, wherein each tile, e.g. may be of rectangular shapeand may comprise one or more blocks (e.g. CTUs), e.g. complete orfractional blocks.

Other variations of the video decoder 30 can be used to decode theencoded picture data 21. For example, the decoder 30 can produce theoutput video stream without the loop filtering unit 320. For example, anon-transform based decoder 30 can inverse-quantize the residual signaldirectly without the inverse-transform processing unit 312 for certainblocks or frames. In another implementation, the video decoder 30 canhave the inverse-quantization unit 310 and the inverse-transformprocessing unit 312 combined into a single unit.

It should be understood that, in the encoder 20 and the decoder 30, aprocessing result of a current step may be further processed and thenoutput to the next step. For example, after interpolation filtering,motion vector derivation or loop filtering, a further operation, such asClip or shift, may be performed on the processing result of theinterpolation filtering, motion vector derivation or loop filtering.

It should be noted that further operations may be applied to the derivedmotion vectors of current block (including but not limit to controlpoint motion vectors of affine mode, sub-block motion vectors in affine,planar, ATMVP modes, temporal motion vectors, and so on). For example,the value of motion vector is constrained to a predefined rangeaccording to its representing bit. If the representing bit of motionvector is bitDepth, then the range is −2{circumflex over( )}(bitDepth−1)˜2{circumflex over ( )}(bitDepth−1)−1, where“{circumflex over ( )}” means exponentiation. For example, if bitDepthis set equal to 16, the range is −32768˜32767; if bitDepth is set equalto 18, the range is −131072˜131071. For example, the value of thederived motion vector (e.g. the MVs of four 4×4 sub-blocks within one8×8 block) is constrained such that the max difference between integerparts of the four 4×4 sub-block MVs is no more than N pixels, such as nomore than 1 pixel. Here provides two methods for constraining the motionvector according to the bitDepth.

FIG. 4 is a schematic diagram of a video coding device 400 according toan embodiment of the disclosure. The video coding device 400 is suitablefor implementing the disclosed embodiments as described herein. In anembodiment, the video coding device 400 may be a decoder such as videodecoder 30 of FIG. 1A or an encoder such as video encoder 20 of FIG. 1A.

The video coding device 400 comprises ingress ports 410 (or input ports410) and receiver units (Rx) 420 for receiving data; a processor, logicunit, or central processing unit (CPU) 430 to process the data;transmitter units (Tx) 440 and egress ports 450 (or output ports 450)for transmitting the data; and a memory 460 for storing the data. Thevideo coding device 400 may also comprise optical-to-electrical (OE)components and electrical-to-optical (EO) components coupled to theingress ports 410, the receiver units 420, the transmitter units 440,and the egress ports 450 for egress or ingress of optical or electricalsignals.

The processor 430 is implemented by hardware and software. The processor430 may be implemented as one or more CPU chips, cores (e.g., as amulti-core processor), FPGAs, ASICs, and DSPs. The processor 430 is incommunication with the ingress ports 410, receiver units 420,transmitter units 440, egress ports 450, and memory 460. The processor430 comprises a coding module 470. The coding module 470 implements thedisclosed embodiments described above. For instance, the coding module470 implements, processes, prepares, or provides the various codingoperations. The inclusion of the coding module 470 therefore provides asubstantial improvement to the functionality of the video coding device400 and effects a transformation of the video coding device 400 to adifferent state. Alternatively, the coding module 470 is implemented asinstructions stored in the memory 460 and executed by the processor 430.

The memory 460 may comprise one or more disks, tape drives, andsolid-state drives and may be used as an over-flow data storage device,to store programs when such programs are selected for execution, and tostore instructions and data that are read during program execution. Thememory 460 may be, for example, volatile and/or non-volatile and may bea read-only memory (ROM), random access memory (RAM), ternarycontent-addressable memory (TCAM), and/or static random-access memory(SRAM).

FIG. 5 is a simplified block diagram of an apparatus 500 that may beused as either or both of the source device 12 and the destinationdevice 14 from FIG. 1 according to an exemplary embodiment.

A processor 502 in the apparatus 500 can be a central processing unit.Alternatively, the processor 502 can be any other type of device, ormultiple devices, capable of manipulating or processing informationnow-existing or hereafter developed. Although the disclosedimplementations can be practiced with a single processor as shown, e.g.,the processor 502, advantages in speed and efficiency can be achievedusing more than one processor.

A memory 504 in the apparatus 500 can be a read only memory (ROM) deviceor a random access memory (RAM) device in an implementation. Any othersuitable type of storage device can be used as the memory 504. Thememory 504 can include code and data 506 that is accessed by theprocessor 502 using a bus 512. The memory 504 can further include anoperating system 508 and application programs 510, the applicationprograms 510 including at least one program that permits the processor502 to perform the methods described here. For example, the applicationprograms 510 can include applications 1 through N, which further includea video coding application that performs the methods described here.

The apparatus 500 can also include one or more output devices, such as adisplay 518. The display 518 may be, in one example, a touch sensitivedisplay that combines a display with a touch sensitive element that isoperable to sense touch inputs. The display 518 can be coupled to theprocessor 502 via the bus 512.

Although depicted here as a single bus, the bus 512 of the apparatus 500can be composed of multiple buses. Further, the secondary storage 514can be directly coupled to the other components of the apparatus 500 orcan be accessed via a network and can comprise a single integrated unitsuch as a memory card or multiple units such as multiple memory cards.The apparatus 500 can thus be implemented in a wide variety ofconfigurations.

The following are definitions of acronyms used herein:

CTB Coding Tree Block CTU Coding Tree Unit CU Coding Unit CVS CodedVideo Sequence JVET Joint Video Experts Team MCTS Motion-ConstrainedTile Set MTU Maximum Transfer Unit NAL Network Abstraction Layer POCPicture Order Count RBSP Raw Byte Sequence Payload SPS SequenceParameter Set VVC Versatile Video Coding WD Working Draft

In general, this disclosure describes methods for signaling of tiles invideo coding that partition pictures. More specifically, this disclosuredescribes methods for signaling of tile partitioning where sometimes thepartitioning scheme is signaled based on the numbers of rows and columnsresulted from the partitioning, and sometimes based on the width andheight of the partitioning results. The description of the techniquesare based on the under-development video coding standard Versatile VideoCoding (VVC) by the joint video experts team (JVET) of ITU-T andISO/IEC. However, the techniques also apply to other video codecspecifications.

Video coding basics are found in Appendix A and are discussed below.

Video compression techniques perform spatial (intra-picture) predictionand/or temporal (inter-picture) prediction to reduce or removeredundancy inherent in video sequences. For block-based video coding, avideo slice (i.e., a video picture or a portion of a video picture) maybe partitioned into video blocks, which may also be referred to astreeblocks, coding tree blocks (CTBs), coding tree units (CTUs), codingunits (CUs) and/or coding nodes. Video blocks in an intra-coded (I)slice of a picture are encoded using spatial prediction with respect toreference samples in neighboring blocks in the same picture. Videoblocks in an inter-coded (P or B) slice of a picture may use spatialprediction with respect to reference samples in neighboring blocks inthe same picture or temporal prediction with respect to referencesamples in other reference pictures. Pictures may be referred to asframes, and reference pictures may be referred to as reference frames.

Spatial or temporal prediction results in a predictive block for a blockto be coded. Residual data represents pixel differences between theoriginal block to be coded and the predictive block. An inter-codedblock is encoded according to a motion vector that points to a block ofreference samples forming the predictive block, and the residual dataindicating the difference between the coded block and the predictiveblock. An intra-coded block is encoded according to an intra-coding modeand the residual data. For further compression, the residual data may betransformed from the pixel domain to a transform domain, resulting inresidual transform coefficients, which then may be quantized. Thequantized transform coefficients, initially arranged in atwo-dimensional array, may be scanned in order to produce aone-dimensional vector of transform coefficients, and entropy coding maybe applied to achieve even more compression.

Video coding standards are discussed.

Video coding standards include ITU-T H.261, ISO/IEC MPEG-1 Part 2, ITU-TH.262 or ISO/IEC MPEG-2 Part 2, ITU-T H.263, ISO/IEC MPEG-4 Part 2,Advanced Video Coding (AVC), also known as ITU-T H.264 or ISO/IEC MPEG-4Part 10, and High Efficiency Video Coding (HEVC), also known as ITU-TH.265 or MPEG-H Part 2. AVC includes extensions such as Scalable VideoCoding (SVC), Multiview Video Coding (MVC) and Multiview Video Codingplus Depth (MVC+D), and 3D AVC (3D-AVC). HEVC includes extensions suchas Scalable HEVC (SHVC), Multiview HEVC (MV-HEVC), and 3D HEVC(3D-HEVC).

There is also a new video coding standard, named Versatile Video Coding(VVC), being developed by the joint video experts team (JVET) of ITU-Tand ISO/IEC. At the time of writing, the latest Working Draft (WD) ofVVC included in JVET-L1001-v5, which is publicly available at:http://phenix.it-sudparis.eu/jvet/doc_end_user/documents/12_Macao/wg11/JVET-L1001-v11.zip.

Picture partitioning schemes in HEVC are discussed.

HEVC includes four different picture partitioning schemes, namelyregular slices, dependent slices, tiles, and Wavefront ParallelProcessing (WPP), which may be applied for Maximum Transfer Unit (MTU)size matching, parallel processing, and reduced end-to-end delay.

Regular slices are similar as in H.264/AVC. Each regular slice isencapsulated in its own NAL unit, and in-picture prediction (intrasample prediction, motion information prediction, coding modeprediction) and entropy coding dependency across slice boundaries aredisabled. Thus, a regular slice can be reconstructed independently fromother regular slices within the same picture (though there may stillhave interdependencies due to loop filtering operations).

The regular slice is the only tool that can be used for parallelizationthat is also available, in virtually identical form, in H.264/AVC.Regular slices based parallelization does not require muchinter-processor or inter-core communication (except for inter-processoror inter-core data sharing for motion compensation when decoding apredictively coded picture, which is typically much heavier thaninter-processor or inter-core data sharing due to in-pictureprediction). However, for the same reason, the use of regular slices canincur substantial coding overhead due to the bit cost of the sliceheader and due to the lack of prediction across the slice boundaries.Further, regular slices (in contrast to the other tools mentioned below)also serve as the key mechanism for bitstream partitioning to match MTUsize requirements, due to the in-picture independence of regular slicesand that each regular slice is encapsulated in its own NAL unit. In manycases, the goal of parallelization and the goal of MTU size matchingplace contradicting demands to the slice layout in a picture. Therealization of this situation led to the development of theparallelization tools mentioned below.

Dependent slices have short slice headers and allow partitioning of thebitstream at treeblock boundaries without breaking any in-pictureprediction. Basically, dependent slices provide fragmentation of regularslices into multiple NAL units, to provide reduced end-to-end delay byallowing a part of a regular slice to be sent out before the encoding ofthe entire regular slice is finished.

In WPP, the picture is partitioned into single rows of coding treeblocks (CTBs). Entropy decoding and prediction are allowed to use datafrom CTBs in other partitions. Parallel processing is possible throughparallel decoding of CTB rows, where the start of the decoding of a CTBrow is delayed by two CTBs, so to ensure that data related to a CTBabove and to the right of the subject CTB is available before thesubject CTB is being decoded. Using this staggered start (which appearslike a wavefront when represented graphically), parallelization ispossible with up to as many processors/cores as the picture contains CTBrows. Because in-picture prediction between neighboring treeblock rowswithin a picture is permitted, the required inter-processor/inter-corecommunication to enable in-picture prediction can be substantial. TheWPP partitioning does not result in the production of additional NALunits compared to when it is not applied, thus WPP is not a tool for MTUsize matching. However, if MTU size matching is required, regular slicescan be used with WPP, with certain coding overhead.

Tiles define horizontal and vertical boundaries that partition a pictureinto tile columns and rows. Tile column runs from the top of a pictureto the bottom of the picture. Likewise, tile row runs from the left ofthe picture to the right of the picture. The number of tiles in apicture can be derived simply as number of tile columns multiply bynumber of tile rows.

The scan order of CTBs is changed to be local within a tile (in theorder of a CTB raster scan of a tile), before decoding the top-left CTBof the next tile in the order of tile raster scan of a picture. Similarto regular slices, tiles break in-picture prediction dependencies aswell as entropy decoding dependencies. However, they do not need to beincluded into individual NAL units (same as WPP in this regard); hencetiles cannot be used for MTU size matching. Each tile can be processedby one processor/core, and the inter-processor/inter-core communicationrequired for in-picture prediction between processing units decodingneighboring tiles is limited to conveying the shared slice header incases a slice is spanning more than one tile, and loop filtering relatedsharing of reconstructed samples and metadata. When more than one tileor WPP segment is included in a slice, the entry point byte offset foreach tile or WPP segment other than the first one in the slice issignaled in the slice header.

For simplicity, restrictions on the application of the four differentpicture partitioning schemes have been specified in HEVC. A given codedvideo sequence cannot include both tiles and wavefronts for most of theprofiles specified in HEVC. For each slice and tile, either or both ofthe following conditions must be fulfilled: 1) all coded treeblocks in aslice belong to the same tile; 2) all coded treeblocks in a tile belongto the same slice. Finally, a wavefront segment contains exactly one CTBrow, and when WPP is in use, if a slice starts within a CTB row, it mustend in the same CTB row.

Tile grouping is discussed.

After the 12th JVET meeting in Macao in October 2018, it was agreed toreplace the concept of slice with tile group. However, at the time ofthis IDF is written, the latest draft of VVC has not included the agreedtile group concept yet. Contribution JVET-L0686, which is publiclyavailable athttp://phenix.it-sudparis.eu/jvet/doc_end_user/documents/12_Macao/wg11/JVET-L0686-v2.zip,contains the text of the agreed tile group. The agreed tile group fromthe 12th JVET meeting allows grouping of one or more tile into a tilegroup in which the tiles that belong to the tile group are consecutivein raster scan order of the picture. For convenience, the draftspecification text according to contribution JVET-L0686 is attachedbelow. For the rest of this document, the tile group described inJVET-L0686 is referred to as raster-scan tile group.

JVET contribution JVET-L0114, which is publicly available athttp://phenix.it-sudparis.eu/jvet/doc_end_user/documents/12_Macao/wg11/JVET-L0114-v1.zip,describes another approach for tile grouping. The tile group that isdescribed therein is constrained such that the tiles that are groupedtogether into a tile group shall form a rectangular shape of area withina picture. For the rest of this document, the tile group described inJVET-L0114 is referred to as rectangular tile group.

Time use in 360° video use-case scenarios.

Picture partitioning using tiles and MCTS are features that are used inthe 3600 video applications. MPEG is currently working on specifying astandard to omnidirection video that includes 3600 video and itsapplications. The standard is named Omnidirectional Media ApplicationFormat (OMAF). At the time of writing, the latest Working Draft (WD) ofOMAF included in MPEG output document N17963, which is available herein:http://wg11.sc29.org/doc_end_user/documents/124_Macao/wg11/w17963.zip.

A distinct feature of omnidirectional video is that only a viewport isdisplayed at any particular time, while in normal video applicationstypically the entire video is displayed. This feature may be utilized toimprove the performance of omnidirectional video systems, throughselective delivery depending on the user's viewport (or any othercriteria, such as recommended viewport timed metadata).Viewport-dependent delivery could be enabled for example by region-wisepacking or viewport-dependent video coding. The performance improvementcould be either or both of lower transmission bandwidth and lowerdecoding complexity compared to conventional omnidirectional videosystems under the same resolution/quality of the video part presented tothe user. Annex D of OMAF specification describes several methods forviewport-dependent operation enabled by the OMAF video media profiles.

One of the described use-case scenarios enabled by viewport-dependentoperation is an MCTS-based approach for achieving 5K effectiveequirectangular projection (ERP) resolution with HEVC-basedviewport-dependent OMAF video profile.

On the in FIG. 6 there are two tile structures with different tile size:4×4 for in case A) and 2×2 B). Of course, higher granularity of gridhave bit-rate overhead due to cross-tile independency, but it is theissue mostly for storing, for transmission of portion of the picturemarked by green color lower granularity require to transmit larger area(red rectangle).

The problems of the existing time structure are discussed.

The current tile structure is defined by a set of tile columns and a setof tile rows. Tile column runs from the top of a picture to the bottomof the picture. Likewise, tile row runs from the left of the picture tothe right of the picture. While such structure makes the definition oftile simpler the signaling of parameters of tile structures could bemore efficient.

In the use-case scenario described herein, for pictures to be deliveredfrom the content provider to the receiver (i.e., OMAF player), the tilestructure is shown in FIG. 6.

For large resolution video (4K, 8K or even higher) the parallelprocessing is used and higher resolution require more processing unitstherefore more granulated tile structure is required. Examples of suchgranularity for common high resolution video are shown in Table 1. Thecase a) on the figure corresponds to HEVC standard with minimum tilesize equal to 4×4 in term of CTUs with size 64×64 pixels. It can benoted that even fixed signaling by Width and Height instead of numberColumns and Rows is more efficient. Moreover, during MCTS extractionprocess updating of the number of columns and rows within tile group isrequired, but if width and height is used for signaling then there is nochange in signaling, because width and height of each tile is the samebefore and after extraction.

In conclusion, depending on the number of tile rows and the number oftile columns for partitioning a picture into tiles, and depending on thenumber of a higher-level tile rows and the number of higher-level tilecolumns for partitioning a next-lower-level tile into high-level tiles,it is sometimes more efficient to signal the partitioning scheme basedon the numbers of rows and columns, and sometimes more efficient tosignal the partitioning scheme based on the width and height of thepartitioning results. Consequently, the current scheme that alwayssignal the partitioning scheme based on the numbers of rows and columnsis not optimal in signaling efficiency.

A technical description and the basic concepts of the present disclosureare provided.

In order to solve the problem listed above, the present disclosurediscloses the following aspects (each of them can be appliedindividually and some of them can be applied in combination):

1) For signaling of tile partitioning, the following steps are used:

a. To use tile width and tile height for defining tile structure of apicture.

b. Define a type of distribution of tile structure by:

i. Tile columns and tile rows in the same style as in HEVC. Note thatthe tile columns and tile rows may be uniform or not uniform in size,same or similarly as in HEVC.

ii. Tile width and tile height. Note that by defining tile distributionusing width and height the uniform or non-uniform distribution could beachieved.

iii. Predetermined distribution pattern.

c. Define the value of signaled parameter for horizontal distributionwhich could be whether the number of columns or the width of the columndepending on the type of horizontal tile distribution.

d. Define the value of signaled parameter for vertical distributionwhich could be whether number of rows or the height of the row dependingon the type of vertical tile distribution.

e. The presence of flag of distribution type could be conditionallysignaled depending on

i. the width and/or height of the picture

ii. the width of a second-level tile for columns and/or height ofsecond-level tile for rows, if a tile is further split into second-leveltile columns and/or second-level tile rows, in which case it can be saidthat there is more than one tile distribution layer

iii. the number of tile units in picture

iv. the number of tile units in higher layer tile

v. the flag of further splitting of the tile

f. For simplicity, distribution type of both vertical and horizontaldirections could be signaled by one flag.

2) For non-uniform distribution signaling by tile width and tile heightcould be used just to define the number of tile columns and tile rows,further tile width and tile height of each tile could be updatedexplicitly.

3) When more than one tile distribution layer is present, there are afew possible implementations possible:

a. The first layer could use fixed uniform or non-uniform distributionand further tile partitioning layers could use another distribution:

i. The type of distribution could be signaled and applied for the wholepartitioning layer.

ii. For simplicity first layer could use fixed tile distribution type bynumber of column and number of rows while the second and further layersuse fixed type of tile distribution by tile width and tile height.

4) Derivation of tile distribution defined by the approach described initem 1)a-1)d is described in the embodiment below in section 4.2 of thisdocument.

A detailed description of the embodiment 1 of the present disclosure isprovided.

This clause documents the embodiment of the inventive aspect 1) of thedisclosure as summarized in clause 4.1. The description is in relativeto the basis text, which is the JVET contribution JVET-L0686. In otherwords, only the delta is described, while the texts in the basis textthat are not mentioned below apply as they are. Modified text relativeto the basis text is highlighted.

The CTB raster and tile scanning process are described.

The variable NumTileColumnsMinus1, specifying the number of tile columnswithin a picture minus 1, and the list ColWidth[i] for i ranging from 0to NumTileColumnsMinus1, inclusive, specifying the width of the i-thtile column in units of CTBs, are derived as follows:

if( uniform_tile_spacing_flag ) {  NumTileColumnsMinus1 =tile_distribution_by_width_flag ?   (PicWidthInCtbsY) /(tile_hor_split_param_minus1[i] + 1)− 1 :   tile_hor_split_param_minus1for( i = 0; i <= NumTileColumnsMinus1; i++ ) ColWidth[ i ] = ( (i + 1) * PicWidthInCtbsY ) / ( NumTileColumnsMinus1 + 1 )−   ( i *PicWidthInCtbsY ) / ( NumTileColumnsMinus1 + 1 ) } else {  ColWidth[NumTileColumnsMinus1 ] = PicWidthInCtbsY (6-1)  for( i = 0; i <NumTileColumnsMinus1; i++ ) {   ColWidth[ i ] =tile_column_width_minu1[i ] + 1   ColWidth[ NumTileColumnsMinus1 ] −=ColWidth[ i ] }  }

The variable NumTileRowsMinus1 specifying the number of tile rows withina picture minus 1, and the list RowHeight[j] for j ranging from 0 toNumTileRowsMinus1, inclusive, specifying the height of the j-th tile rowin units of CTBs, are derived as follows:

 if( uniform_tile_spacing_flag ) {  NumTileRowsMinus1 =tile_distribution_by_height_flag ?    (PicHeightInCtbsY) /(tile_ver_split_param_minus1[ i ] + 1)− 1 :    tile_ver_split_param_minus1   for( j = 0; j <= NumTileRowsMinus1;j++ )  RowHeight[ j ] = ( ( j + 1 ) * PicHeightInCtbsY ) / (NumTileRowsMinus1 + 1 )−    ( j * PicHeightInCtbsY ) / (NumTileRowsMinus1 + 1 ) } else {  RowHeight[ NumTileRowsMinus1 ] =PicHeightInCtbsY (6-2)  for( j = 0; j < NumTileRowsMinus1; j++ ) {  RowHeight[ j ] = tile_row_height_minus1[ j ] + 1   RowHeight[NumTileRowsMinus1 ] −= RowHeight[ j ]  } }

The picture parameter set RBSP syntax is provided.

Descriptor pic_parameter_set_rbsp( ) {  pps_pic_parameter_set_id ue(v) pps_seq_parameter_set_id ue(v)  transform_skip_enabled_flag u(1) single_tile_in_pic_flag u(1)  if( !single_tile_in_pic_flag ) {  tile_distribution_by_width_flag u(1)   num_tile_hor_split_param_minus1ue(v)   tile_distribution_by_height_flag u(1)  num_tile_ver_split_param_minus1 ue(v)   uniform_tile_spacing_flag u(1)  if( !uniform_tile_spacing_flag ) {    for( i = 0; i <NumTileColumnsMinus1; i++ )     tile_column_width_minus1[ i ] ue(v)   for( i = 0; i < NumTileRowsMinus1; i++ )     tile_row_height_minus1[i ] ue(v)   }   loop_filter_across_tiles_enabled_flag u(1)  } rbsp_trailing_bits( ) }

The picture parameter set RBSP semantics are as follows.

tile_distribution_by_width_flag specifies whether the number of columnsor column width will be signaled for columns distribution. When notpresent, the value of tile_distribution_by_width_flag is inferred to beequal to 0.

tile_distribution_by_height_flag specifies whether the number of rows orrow height will be signaled for rows distribution. When not present, thevalue of tile_distribution_by_height_flag is inferred to be equal to 0.

num_tile_hor_split_param_minus1 plus 1 specifies the number of tilecolumns partitioning the picture or num_tile_column_width_minus1depending on the value of tile_distribution_by_width_flag. When notpresent, the value of num_tile_hor_split_param_minus1 is inferred to beequal to 0.

num_tile_ver_split_param_minus1 plus 1 specifies the number of tile rowspartitioning the picture or num_tile_rows_height_minus1 depending on thevalue of tile_distribution_by_height_flag. When not present, the valueof num_tile_ver_split_param_minus1 is inferred to be equal to 0.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and could be made without departing from the spirit and scopedisclosed herein.

FIG. 7 shows the corresponding method of decoding of a video bitstreamimplemented by a decoding device, wherein the video bitstream includesdata representing a coded picture comprising tile columns. The decodingmethod comprises the steps of:

S701, obtaining a syntax element by parsing the video bitstream, whereinthe syntax element is used to derive the width of the tile columns,wherein the width of the tile columns are uniform.

S702, predicting the picture according the width of the tile columns.

For specific features in the embodiments of the present disclosure,refer to related the decoding method embodiments above. Details are notdescribed herein again.

FIG. 8 shows the corresponding method of decoding of a video bitstreamimplemented by a decoding device, wherein the video bitstream includesdata representing a coded picture comprising plurality of tile columns.The decoding method comprises the steps of:

S801, obtaining a syntax element by parsing the video bitstream, whereinthe syntax element is used to derive the width of a tile column of theplurality of tile columns.

S802, determining the number of the plurality of tile columns based onthe width of the tile column.

S803, predicting the picture according the width of the tile columnand/or the number of the plurality of tile columns.

For specific features in the embodiments of the present disclosure,refer to related the decoding method embodiments above. Details are notdescribed herein again.

FIG. 9 shows the corresponding method of coding implemented by anencoding device, the coding method comprises the steps of:

S901, obtaining the width of tile columns in a picture in the process ofencoding the picture, wherein the width of the tile columns are uniform.

S902, obtaining a syntax element used to derive the width of the tilecolumns according to the width of tile columns.

S903, encoding the syntax element into the bitstream of the picture.

For specific features in the embodiments of the present disclosure,refer to related the decoding method embodiments above. Details are notdescribed herein again.

FIG. 10 shows the corresponding method of coding implemented by anencoding device, the coding method comprises the steps of:

S1001, obtaining the width of a tile column of the plurality of tilecolumns in a picture.

S1002, determining the number of the plurality of tile columns based onthe width of the tile column.

S1003, predicting the picture according the width of the tile columnand/or the number of the plurality of tile columns.

For specific features in the embodiments of the present disclosure,refer to related the decoding method embodiments above. Details are notdescribed herein again.

FIG. 11 shows a decoding device (decoder) 1100 for decoding a videobitstream. The video bitstream includes data representing a codedpicture comprising tile columns, the decoding device comprising: aparsing unit 1110 configured to obtain a syntax element by parsing thevideo bitstream, wherein the syntax element is used to derive the widthof the tile columns, wherein the width of the tile columns are uniform;a predicting unit 1120 configured to encode the syntax element into thebitstream of the picture.

Wherein the parsing unit 1110 may be the entropy decoding unit 304.

Wherein the predicting unit 1120 may be the inter prediction unit 344 orintra prediction unit 354.

For specific functions of units in the decoder 1100 in the embodimentsof the present disclosure, refer to related descriptions of the decodingmethod embodiment of the present disclosure. Details are not describedherein again.

The units in the decoder 1100 may be implemented by software or circuit.

The decoder 1100 may be the decoder 30, video coding device 400, orapparatus 500, or part of the decoder 30, video coding device 400, orapparatus 500.

FIG. 12 shows a decoding device (decoder) 1200 for decoding a videobitstream. The video bitstream includes data representing a codedpicture comprising plurality of tile columns, the decoding devicecomprising: a parsing unit 1210 configured to obtain a syntax element byparsing the video bitstream, wherein the syntax element is used toderive the width of a tile column of the plurality of tile columns; adetermining unit 1220, configured to determine the number of theplurality of tile columns based on the width of the tile column; apredicting unit 1230, configured to predict the picture according thewidth of the tile column and/or the number of the plurality of tilecolumns.

Wherein the parsing unit 1210 may be the entropy decoding unit 304.

Wherein the determining unit 1220 may be the inter prediction unit 344or intra prediction unit 354, or the picture partitioning unit (notdepicted in FIG. 3)

Wherein the predicting unit 1230 may be the inter prediction unit 344 orintra prediction unit 354.

For specific functions of units in the decoder 1200 in the embodimentsof the present disclosure, refer to related descriptions of the decodingmethod embodiment of the present disclosure. Details are not describedherein again.

The units in the decoder 1200 may be implemented by software or circuit.

The decoder 1200 may be the decoder 30, video coding device 400, orapparatus 500, or part of the decoder 30, video coding device 400, orapparatus 500.

FIG. 13 shows an encoding device (encoder) 1300 for encoding of a videobitstream. The encoding device comprises: an obtaining unit 1310,configured to obtain the width of tile columns in a picture in theprocess of encoding the picture, wherein the width of the tile columnsare uniform; and obtain a syntax element used to derive the width of thetile columns according to the width of tile columns; an encoding unit1320, configured to encode the syntax element into the bitstream of thepicture.

Wherein the obtaining unit 1310 may be the inter prediction unit 244 orintra prediction unit 254, or the picture partitioning unit (notdepicted in FIG. 2)

Wherein the encoding unit 1320 may be the entropy encoding unit 270.

For specific functions of units in the encoder 1300 in the embodimentsof the present disclosure, refer to related descriptions of the encodingmethod embodiment of the present disclosure. Details are not describedherein again.

The units in the encoder 1300 may be implemented by software or circuit.

The encoder 1300 may be the encoder 20, video coding device 400, orapparatus 500, or part of the encoder 20, video coding device 400, orapparatus 500.

FIG. 14 shows an encoding device (encoder) 1400 for encoding of a videobitstream. The encoding device comprises: an obtaining unit 1410,configured to obtain the width of a tile column of the plurality of tilecolumns in a picture; a determining unit 1420, configured to determinethe number of the plurality of tile columns based on the width of thetile column; an predicting unit 1430, configured to predict the pictureaccording the width of the tile column and/or the number of theplurality of tile columns.

Wherein the obtaining unit 1410 may be the inter prediction unit 244 orintra prediction unit 254, or the picture partitioning unit (notdepicted in FIG. 2)

Wherein the determining unit 1420 may be the inter prediction unit 244or intra prediction unit 254, or the picture partitioning unit (notdepicted in FIG. 2)

Wherein predicting unit 1430 may be the inter prediction unit 244 orintra prediction unit 254.

For specific functions of units in the encoder 1400 in the embodimentsof the present disclosure, refer to related descriptions of the encodingmethod embodiment of the present disclosure. Details are not describedherein again.

The units in the encoder 1400 may be implemented by software or circuit.

The encoder 1400 may be the encoder 20, video coding device 400, orapparatus 500, or part of the encoder 20, video coding device 400, orapparatus 500.

Following is an explanation of the applications of the encoding methodas well as the decoding method as shown in the above-mentionedembodiments, and a system using them.

FIG. 15 is a block diagram showing a content supply system 3100 forrealizing content distribution service. This content supply system 3100includes capture device 3102, terminal device 3106, and optionallyincludes display 3126. The capture device 3102 communicates with theterminal device 3106 over communication link 3104. The communicationlink may include the communication channel 13 described above. Thecommunication link 3104 includes but not limited to WIFI, Ethernet,Cable, wireless (3G/4G/5G), USB, or any kind of combination thereof, orthe like.

The capture device 3102 generates data, and may encode the data by theencoding method as shown in the above embodiments. Alternatively, thecapture device 3102 may distribute the data to a streaming server (notshown in the Figures), and the server encodes the data and transmits theencoded data to the terminal device 3106. The capture device 3102includes but not limited to camera, smart phone or Pad, computer orlaptop, video conference system, PDA, vehicle mounted device, or acombination of any of them, or the like. For example, the capture device3102 may include the source device 12 as described above. When the dataincludes video, the video encoder 20 included in the capture device 3102may actually perform video encoding processing. When the data includesaudio (i.e., voice), an audio encoder included in the capture device3102 may actually perform audio encoding processing. For some practicalscenarios, the capture device 3102 distributes the encoded video andaudio data by multiplexing them together. For other practical scenarios,for example in the video conference system, the encoded audio data andthe encoded video data are not multiplexed. Capture device 3102distributes the encoded audio data and the encoded video data to theterminal device 3106 separately.

In the content supply system 3100, the terminal device 310 receives andreproduces the encoded data. The terminal device 3106 could be a devicewith data receiving and recovering capability, such as smart phone orPad 3108, computer or laptop 3110, network video recorder (NVR)/digitalvideo recorder (DVR) 3112, TV 3114, set top box (STB) 3116, videoconference system 3118, video surveillance system 3120, personal digitalassistant (PDA) 3122, vehicle mounted device 3124, or a combination ofany of them, or the like capable of decoding the above-mentioned encodeddata. For example, the terminal device 3106 may include the destinationdevice 14 as described above. When the encoded data includes video, thevideo decoder 30 included in the terminal device is prioritized toperform video decoding. When the encoded data includes audio, an audiodecoder included in the terminal device is prioritized to perform audiodecoding processing.

For a terminal device with its display, for example, smart phone or Pad3108, computer or laptop 3110, network video recorder (NVR)/digitalvideo recorder (DVR) 3112, TV 3114, personal digital assistant (PDA)3122, or vehicle mounted device 3124, the terminal device can feed thedecoded data to its display. For a terminal device equipped with nodisplay, for example, STB 3116, video conference system 3118, or videosurveillance system 3120, an external display 3126 is contacted thereinto receive and show the decoded data.

When each device in this system performs encoding or decoding, thepicture encoding device or the picture decoding device, as shown in theabove-mentioned embodiments, can be used.

FIG. 16 is a diagram showing a structure of an example of the terminaldevice 3106. After the terminal device 3106 receives stream from thecapture device 3102, the protocol proceeding unit 3202 analyzes thetransmission protocol of the stream. The protocol includes but notlimited to Real Time Streaming Protocol (RTSP), Hyper Text TransferProtocol (HTTP), HTTP Live streaming protocol (HLS), MPEG-DASH,Real-time Transport protocol (RTP), Real Time Messaging Protocol (RTMP),or any kind of combination thereof, or the like.

After the protocol proceeding unit 3202 processes the stream, streamfile is generated. The file is outputted to a demultiplexing unit 3204.The demultiplexing unit 3204 can separate the multiplexed data into theencoded audio data and the encoded video data. As described above, forsome practical scenarios, for example in the video conference system,the encoded audio data and the encoded video data are not multiplexed.In this situation, the encoded data is transmitted to video decoder 3206and audio decoder 3208 without through the demultiplexing unit 3204.

Via the demultiplexing processing, video elementary stream (ES), audioES, and optionally subtitle are generated. The video decoder 3206, whichincludes the video decoder 30 as explained in the above mentionedembodiments, decodes the video ES by the decoding method as shown in theabove-mentioned embodiments to generate video frame, and feeds this datato the synchronous unit 3212. The audio decoder 3208, decodes the audioES to generate audio frame, and feeds this data to the synchronous unit3212. Alternatively, the video frame may store in a buffer (not shown inFIG. Y) before feeding it to the synchronous unit 3212. Similarly, theaudio frame may store in a buffer (not shown in FIG. Y) before feedingit to the synchronous unit 3212.

The synchronous unit 3212 synchronizes the video frame and the audioframe, and supplies the video/audio to a video/audio display 3214. Forexample, the synchronous unit 3212 synchronizes the presentation of thevideo and audio information. Information may code in the syntax usingtime stamps concerning the presentation of coded audio and visual dataand time stamps concerning the delivery of the data stream itself.

If subtitle is included in the stream, the subtitle decoder 3210 decodesthe subtitle, and synchronizes it with the video frame and the audioframe, and supplies the video/audio/subtitle to a video/audio/subtitledisplay 3216.

The present disclosure is not limited to the above-mentioned system, andeither the picture encoding device or the picture decoding device in theabove-mentioned embodiments can be incorporated into other system, forexample, a car system.

Mathematical Operators

The mathematical operators used in this application are similar to thoseused in the C programming language. However, the results of integerdivision and arithmetic shift operations are defined more precisely, andadditional operations are defined, such as exponentiation andreal-valued division. Numbering and counting conventions generally beginfrom 0, e.g., “the first” is equivalent to the 0-th, “the second” isequivalent to the 1-th, etc.

Arithmetic Operators

The following arithmetic operators are defined as follows:

-   + Addition-   − Subtraction (as a two-argument operator) or negation (as a unary    prefix operator)-   * Multiplication, including matrix multiplication-   x^(y) Exponentiation. Specifies x to the power of y. In other    contexts, such notation is used for superscripting not intended for    interpretation as exponentiation.-   / Integer division with truncation of the result toward zero. For    example, 7/4 and −7/−4 are truncated to 1 and −7/4 and 7/−4 are    truncated to −1.-   ÷ rounding is intended.

$\frac{x}{y}$

Used to denote division in mathematical equations where no truncation orrounding is intended.

$\sum\limits_{i = x}^{y}\;{f(i)}$

The summation of f(i) with i taking all integer values from x up to andincluding y.

-   x % y Modulus. Remainder of x divided by y, defined only for    integers x and y with x>0 and y>0.

Logical Operators

The following logical operators are defined as follows:

-   -   x && y Boolean logical “and” of x and y    -   x∥y Boolean logical “or” of x and y    -   ! Boolean logical “not”    -   x?y:z If x is TRUE or not equal to 0, evaluates to the value of        y; otherwise, evaluates to the value of z.

Relational Operators

The following relational operators are defined as follows:

-   -   > Greater than    -   >= Greater than or equal to    -   < Less than    -   <= Less than or equal to    -   == Equal to    -   != Not equal to

When a relational operator is applied to a syntax element or variablethat has been assigned the value “na” (not applicable), the value “na”is treated as a distinct value for the syntax element or variable. Thevalue “na” is considered not to be equal to any other value.

Bit-Wise Operators

The following bit-wise operators are defined as follows:

-   -   & Bit-wise “and”. When operating on integer arguments, operates        on a two's complement representation of the integer value. When        operating on a binary argument that contains fewer bits than        another argument, the shorter argument is extended by adding        more significant bits equal to 0.    -   Bit-wise “or”. When operating on integer arguments, operates on        a two's complement representation of the integer value. When        operating on a binary argument that contains fewer bits than        another argument, the shorter argument is extended by adding        more significant bits equal to 0.    -   {circumflex over ( )} Bit-wise “exclusive or”. When operating on        integer arguments, operates on a two's complement representation        of the integer value. When operating on a binary argument that        contains fewer bits than another argument, the shorter argument        is extended by adding more significant bits equal to 0.    -   x>>y Arithmetic right shift of a two's complement integer        representation of x by y binary digits. This function is defined        only for non-negative integer values of y. Bits shifted into the        most significant bits (MSBs) as a result of the right shift have        a value equal to the MSB of x prior to the shift operation.    -   x<<y Arithmetic left shift of a two's complement integer        representation of x by y binary digits. This function is defined        only for non-negative integer values of y. Bits shifted into the        least significant bits (LSBs) as a result of the left shift have        a value equal to 0.

Assignment Operators

The following arithmetic operators are defined as follows:

-   -   = Assignment operator    -   ++ Increment, i.e., x++ is equivalent to x=x+1; when used in an        array index, evaluates to the value of the variable prior to the        increment operation.    -   −− Decrement, i.e., x−− is equivalent to x=x−1; when used in an        array index, evaluates to the value of the variable prior to the        decrement operation.    -   += Increment by amount specified, i.e., x+=3 is equivalent to        x=x+3, and x+=(−3) is equivalent to x=x+(−3).    -   −=Decrement by amount specified, i.e., x−=3 is equivalent to        x=x−3, and x−=(−3) is equivalent to x=x−(−3).

Range Notation

The following notation is used to specify a range of values:

-   -   x=y . . . zx takes on integer values starting from y to z,        inclusive, with x, y, and z being integer numbers and z being        greater than y.

Mathematical Functions

The following mathematical functions are defined:

${{Abs}(x)} = \left\{ \begin{matrix}x & ; & {x\mspace{14mu}\text{>=}\mspace{14mu} 0} \\{- x} & ; & {x < 0}\end{matrix} \right.$

-   -   A sin(x) the trigonometric inverse sine function, operating on        an argument x that is        in the range of −1.0 to 1.0, inclusive, with an output value in        the range of        −π÷2 to π÷2, inclusive, in units of radians    -   A tan(x) the trigonometric inverse tangent function, operating        on an argument x, with        an output value in the range of −π÷2 to π÷2, inclusive, in units        of radians

${{Atan}\; 2\left( {y,x} \right)} = \left\{ \begin{matrix}{{Atan}\left( \frac{y}{x} \right)} & ; & {x > 0} \\{{{Atan}\left( \frac{y}{x} \right)} + \pi} & ; & {{x < 0}\&\&{y\mspace{14mu}\text{>=}\mspace{14mu} 0}} \\{{{Atan}\left( \frac{y}{x\;} \right)} - \pi} & ; & {{x < 0}\&\&{y < 0}} \\{+ \frac{\pi}{2}} & ; & {{x\mspace{14mu}\text{==}\mspace{14mu} 0}\&\&{y\mspace{14mu}\text{>=}\mspace{14mu} 0}} \\{- \frac{\pi}{2}} & ; & {otherwise}\end{matrix} \right.$

-   -   Ceil(x) the smallest integer greater than or equal to x.    -   Clip1_(Y)(x)=Clip3(0, (1<<BitDepth_(Y))−1, x)    -   Clip1_(C)(x)=Clip3(0, (1<<BitDepth_(C))−1, x)

${{Clip}\; 3\left( {x,y,z} \right)} = \left\{ \begin{matrix}x & ; & {z < x} \\y & ; & {z > y} \\z & ; & {otherwise}\end{matrix} \right.$

-   -   Cos(x) the trigonometric cosine function operating on an        argument x in units of radians.    -   Floor(x) the largest integer less than or equal to x.

${{GetCurrMsb}\left( {a,b,c,d} \right)} = \left\{ \begin{matrix}{c + d} & ; & {b - {a\mspace{14mu}\text{>=}\mspace{14mu} d\text{/}2}} \\{c - d} & ; & {{a - b} > {d\text{/}2}} \\c & ; & {otherwise}\end{matrix} \right.$

-   -   Ln(x) the natural logarithm of x (the base-e logarithm, where e        is the natural logarithm base constant 2.718 281 828 . . . ).    -   Log 2(x) the base-2 logarithm of x.    -   Log 10(x) the base-10 logarithm of x.

${{Min}\left( {x,y} \right)} = \left\{ {{\begin{matrix}x & ; & {x\mspace{14mu}\text{<=}\mspace{14mu} y} \\y & ; & {x > y}\end{matrix}{{Max}\left( {x,y} \right)}} = \left\{ \begin{matrix}x & ; & {x\mspace{14mu}\text{>=}\mspace{14mu} y} \\y & ; & {x < y}\end{matrix} \right.} \right.$

-   -   Round(x)=Sign(x)*Floor(Abs(x)+0.5)

${{Sign}(x)} = \left\{ \begin{matrix}1 & ; & {x > 0} \\0 & ; & {x\mspace{14mu}\text{==}\mspace{14mu} 0} \\{- 1} & ; & {x < 0}\end{matrix} \right.$

-   -   Sin(x) the trigonometric sine function operating on an argument        x in units of radians    -   Sqrt(x)=√{square root over (x)}    -   Swap(x, y)=(y, x)    -   Tan(x) the trigonometric tangent function operating on an        argument x in units of radians

Order of Operation Precedence

When an order of precedence in an expression is not indicated explicitlyby use of parentheses, the following rules apply:

Operations of a higher precedence are evaluated before any operation ofa lower precedence.

Operations of the same precedence are evaluated sequentially from leftto right.

The table below specifies the precedence of operations from highest tolowest; a higher position in the table indicates a higher precedence.

For those operators that are also used in the C programming language,the order of precedence used in this Specification is the same as usedin the C programming language.

Table: Operation precedence from highest (at top of table) to lowest (atbottom of table)

operations (with operands x, y, and z)  ″x++″, ″x−−″  ″!x″, ″−x″ (as aunary prefix operator)  x^(y)${{\,^{''}x}*y^{''}\,},{{\,^{''}x}\text{/}y^{''}\,},{{{\,^{''}x} \div y^{''}}\,},{''{\,\frac{x}{y}}''},{{\,^{''}x}\mspace{14mu}\%\mspace{14mu} y^{''}\,}$ ″x + y″, ″x − y″ (as a two-argument operator),$''{\sum\limits_{i = x}^{y}{f(i)}^{''}}$  ″x << y″, ″x >> y″  ″x < y″,″x <= y″, ″x > y″, ″x >= y″  ″x == y″, ″x != y″  ″x & y″  ″x|y″  ″x &&y″  ″x∥y″  ″x ? y:z″  ″x . . . y″  ″x = y″, ″x += y″, ″x −= y″

Text Description of Logical Operations

In the text, a statement of logical operations as would be describedmathematically in the following form:

if( condition 0)   statement 0 else if( condition 1 )   statement 1 else/* informative remark on remaining condition */   statement n  may bedescribed in the following manner: as follows / ... the followingapplies: If condition 0, statement 0 Otherwise, if condition 1,statement 1 ... Otherwise (informative remark on remaining condition),statement n

Each “If . . . Otherwise, if . . . Otherwise, . . . ” statement in thetext is introduced with “ . . . as follows” or “ . . . the followingapplies” immediately followed by “If . . . ”. The last condition of the“If . . . Otherwise, if . . . Otherwise, . . . ” is always an“Otherwise, . . . ”. Interleaved “If . . . Otherwise, if . . .Otherwise, . . . ” statements can be identified by matching “ . . . asfollows” or “ . . . the following applies” with the ending “Otherwise, .. . ”.

In the text, a statement of logical operations as would be describedmathematically in the following form:

if( condition 0a && condition 0b )   statement 0 else if( condition 1a || condition 1b )   statement 1 ... else   statement n  may be describedin the following manner:  ... as follows / ... the following applies: Ifall of the following conditions are true, statement 0:   condition 0a  condition 0b Otherwise, if one or more of the following conditions aretrue, statement 1:   condition 1a   condition 1b ... Otherwise,statement n

In the text, a statement of logical operations as would be describedmathematically in the following form:

  if( condition 0)   statement 0 if( condition 1 )   statement 1  may bedescribed in the following manner: When condition 0, statement 0 Whencondition 1, statement 1

In one or more examples, the functions described may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored on or transmitted over as oneor more instructions or code on a computer-readable medium and executedby a hardware-based processing unit. Computer-readable media may includecomputer-readable storage media, which corresponds to a tangible mediumsuch as data storage media, or communication media including any mediumthat facilitates transfer of a computer program from one place toanother, e.g., according to a communication protocol. In this manner,computer-readable media generally may correspond to (1) tangiblecomputer-readable storage media which is non-transitory or (2) acommunication medium such as a signal or carrier wave. Data storagemedia may be any available media that can be accessed by one or morecomputers or one or more processors to retrieve instructions, codeand/or data structures for implementation of the techniques described inthis disclosure. A computer program product may include acomputer-readable medium.

By way of example, and not limitation, such computer-readable storagemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage, or other magnetic storage devices, flashmemory, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if instructions are transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. It should be understood, however, thatcomputer-readable storage media and data storage media do not includeconnections, carrier waves, signals, or other transitory media, but areinstead directed to non-transitory, tangible storage media. Disk anddisc, as used herein, includes compact disc (CD), laser disc, opticaldisc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated hardware and/or software modules configured for encoding anddecoding, or incorporated in a combined codec. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses, including a wireless handset, an integratedcircuit (IC) or a set of ICs (e.g., a chip set). Various components,modules, or units are described in this disclosure to emphasizefunctional aspects of devices configured to perform the disclosedtechniques, but do not necessarily require realization by differenthardware units. Rather, as described above, various units may becombined in a codec hardware unit or provided by a collection ofinteroperative hardware units, including one or more processors asdescribed above, in conjunction with suitable software and/or firmware.

While several embodiments have been provided in the present disclosure,it may be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, components, techniques, ormethods without departing from the scope of the present disclosure.Other examples of changes, substitutions, and alterations areascertainable by one skilled in the art and may be made withoutdeparting from the spirit and scope disclosed herein.

What is claimed is:
 1. A method for decoding of a video bitstreamimplemented by a decoding device, wherein the video bitstream includesdata representing a coded picture comprising tile columns, comprising:obtaining a syntax element by parsing the video bitstream, wherein thesyntax element is used to derive a width of the tile columns, whereinthe width of the tile columns is uniform; and predicting the codedpicture according to the width of the tile columns.
 2. The method ofclaim 1, wherein the width of the tile columns are the same.
 3. Themethod of claim 1, wherein the tile columns comprise at least twocolumns.
 4. A method for decoding of a video bitstream implemented by adecoding device, wherein the video bitstream includes data representinga coded picture comprising a plurality of tile columns, comprising:obtaining a syntax element by parsing the video bitstream, wherein thesyntax element is used to derive a width of a tile column of theplurality of tile columns; determining a number of the plurality of tilecolumns based on the width of the tile column; and predicting the codedpicture according to one or more of the width of the tile column and thenumber of the plurality of tile columns.
 5. The method of claim 4,wherein the plurality of tile columns comprise one or more tile columnsof which the width is uniform and the one or more tile columns comprisethe tile column, the obtaining the syntax element by parsing the videobitstream comprises: obtaining the syntax element by parsing the videobitstream, wherein the syntax element is used to derive the width of theone or more tile columns, wherein the width of the tile column comprisesthe width of the one or more tile columns.
 6. The method of claim 5,wherein the width of the one or more tile columns are the same.
 7. Themethod of claim 5, wherein the one or more tile columns comprise atleast two columns.
 8. A method of coding implemented by an encodingdevice, comprising: obtaining a width of tile columns in a picture in aprocess of encoding the picture, wherein the width of the tile columnsis uniform; obtaining a syntax element used to derive the width of thetile columns according to the width of tile columns; and encoding thesyntax element into a bitstream of the picture.
 9. The method of claim8, wherein the width of the tile columns are the same.
 10. The method ofclaim 8, wherein the tile columns comprise at least two columns.
 11. Amethod of coding implemented by an encoding device, comprising:obtaining a width of a tile column of a plurality of tile columns in apicture; determining a number of the plurality of tile columns based onthe width of the tile column; and predicting the picture according toone or more of the width of the tile column and the number of theplurality of tile columns.
 12. The method of claim 11, wherein theplurality of tile columns comprises one or more tile columns of whichthe width is uniform, the one or more tile columns comprise the tilecolumn, and the width of the tile column comprises the width of the oneor more tile columns.
 13. The method of claim 12, wherein the width ofthe one or more tile columns are the same.
 14. The method of claim 12,wherein the one or more tile columns comprise at least two columns. 15.A decoding device for decoding of a video bitstream, wherein the videobitstream includes data representing a coded picture comprising tilecolumns, the decoding device comprising: a memory storing instructions;a processor coupled to the memory, the processor configured to executethe instructions to cause the decoding device to: obtain a syntaxelement by parsing the video bitstream, wherein the syntax element isused to derive a width of the tile columns, wherein the width of thetile columns is uniform; and predict the coded picture according to thewidth of the tile columns.
 16. The decoding device of claim 15, whereinthe width of the tile columns are the same.
 17. The decoding device ofclaim 15, wherein the tile columns comprise at least two columns.
 18. Adecoding device for decoding of a video bitstream, wherein the videobitstream includes data representing a coded picture comprising aplurality of tile columns, the decoding device comprising: a memorystoring instructions; a processor coupled to the memory, the processorconfigured to execute the instructions to cause the decoding device to:obtain a syntax element by parsing the video bitstream, wherein thesyntax element is used to derive a width of a tile column of theplurality of tile columns; determine a number of the plurality of tilecolumns based on the width of the tile column; and predict the codedpicture according to one or more of the width of the tile column and thenumber of the plurality of tile columns.
 19. The decoding device ofclaim 18, wherein one or more tile columns in the plurality of tilecolumns have a uniform width, and wherein the processor is configured toobtain the syntax element by parsing the video bitstream, wherein thesyntax element is used to derive the width of the one or more tilecolumns, and wherein the width of the tile column comprises the width ofthe one or more tile columns.
 20. The decoding device of claim 19,wherein the width of the one or more tile columns are the same.
 21. Thedecoding device of claim 19, wherein the one or more tile columnscomprise at least two columns.
 22. An encoding device, the encodingdevice comprising: a memory storing instructions; a processor coupled tothe memory, the processor configured to execute the instructions tocause the encoding device to: obtain a width of tile columns in apicture in the process of encoding the picture, wherein the width of thetile columns is uniform; and obtain a syntax element used to derive thewidth of the tile columns according to the width of tile columns; andencode the syntax element into a bitstream of the picture.
 23. Theencoding device of claim 22, wherein the width of the tile columns arethe same.
 24. The encoding device of claim 22, wherein the tile columnscomprise at least two columns.
 25. An encoding device, the encodingdevice comprising: a memory storing instructions; a processor coupled tothe memory, the processor configured to execute the instructions tocause the encoding device to: obtain a width of a tile column of aplurality of tile columns in a picture; determine a number of theplurality of tile columns based on the width of the tile column; andpredict the picture according to one or more of the width of the tilecolumn and the number of the plurality of tile columns.
 26. The encodingdevice of claim 25, wherein the plurality of tile columns comprise oneor more tile columns of which the width is uniform, the one or more tilecolumns comprise the tile column, and the width of the tile columncomprises the width of the one or more tile columns.
 27. The encodingdevice of claim 26, wherein the width of the one or more tile columnsare the same.
 28. The encoding device of claim 26, wherein the one ormore tile columns comprise at least two columns.